Drilling fluid composition and process



May 3, 1960 STORMER vasgosirv OF cLmrwarm nmums FLUID.

E, 5. KING Er AL DRILLING FLUID COMPOSITION AND PROCESS v Filed May 25,1959 MIXTURE OFPHOSPHATES AND THlNNER OF OUR \NVENTION- 0.5#/bbl. At pH9.5 In Wyoming Benfom'fe Mud,

aged 24- Hr. m |50F.

- OATIbbLpHQJ IO 20 3O A=- SODIUM PYRoPHosPHATE a= somum TETRAFHOSPHATE'0=+ somum HEXAMETAPHOSPMTE 3:0 500mm Acm PYROPHOSPHRTE i=0 sovlumTmPotxPnosmATE Psaoem 'oF' cmfiaex mospmrrs m MIXTURE uvmvr ona. Carlfldo/p/rson ATTORNEK Our invention and discovery relates to improvementsin drilling fluids resulting from a' novel combination of clays andspecially treated sulfonated ,lignin-containing material.

More particularly burinvention relates to an improved vdrilling fluid ormud composition or combination, and

to aprocess for use thereof. Thislrnud combinationmay be formulated tofunction as water base drilling muds, for example and not limitation asfresh waterfr'nud, as lime base mud, as gypsum mud, asv calcium chloridemud,

[as-salt contaminated or sea watermudsand inemulsion mud systems.Furthermore, themud combination is usable over the entire pH rangeofdrilling-mud fluids used .in the field. A particularly nolvel 'rormrereur'mud system is the combination with gypsummhichis especially usefulin.drill in g oil wells when anhydrite is vencountered. QHeret fQre," a,well recognized fact is that sulfonated ag in-containin additives suchas those derived from ,spent sulfite liquor are effective as thinnersinlime base rnuds but such are notuseful ,as thinners in fresh water muds.

Moreover, our improved mud combination is characterized by stability tohigh temperature and by effectiveness in resisting the deterioratingeffects of contaminants encountered in drilling. Such effectiveness isparticularly I advantageous in drilling deep wells wherehigh temperatureand pressure exist. w i

.Our invention .and discoveryher ein relates primarily and fundamentallyto-the providing of a novel combination of .drilling mud, clay andsulfonated lignin-containing material whereby there results drilling.muds of newly .found properties. It would be difficult to find a'inoresensitive test of the increased effectiveness of the components of ourinvention than .those required to meet the properties of said drillingmuds, w

The improved effectiveness of the components of the sulfonatedlignin-containing material provided by our invention and discoveryrenders them suitable asia drilling mud additive, or as the basefromwhich .an improved I drilling mud can be formed, which mud ischaracterized by having greatly improved properties.

This application is .a. continuation-in-part of our co endingapplication Serial No. 433,794, filed'June 1, "11954, entitled Processof Improving the Effectiveness er the Components of Spent .SulfiteLiquor and the Products Thereof"; our copending application Serial No.539,542, filed October it), 1955, entitled Process of Improving theEffectiveness of the Components of Spent Sulfite Liquor and the ProductsThereof;

our copending application Serial No. 769,185, filed Octoberj23, 1958,entitled A Process'forjProviding an Improved Drilling Fluid and'theProduct Thereof;

our copending application Serial 110,789,775, filed Janiuary' 29, l959,entitled A Processffor Providing Im 1 proved Drilling Mud of Clay and aMetal Lignosulfonate and the Product Thereof; and our copending applica-'tion Serial No. 806,974, filed April '16, 1959, entitled An ImprovedGypsum Base Drilling-Fluid and the Products United States PatentPatented r May 3, 1960 Thmoh e methods or treating sulfonated ugniicontaining material through oxidation and s' altlfo in improving thedispersive properties of said sulfon lignin-containing material and thecombinationof said additive products with clay and water in formingdrilling muds are completely disclosed in said copending applications.Furthermore the unexpected resistance ofgsuch muds to the contaminantsencountered in oil'well'driHing was also set forth. The outstandingproperties of suitable magnitude which characterize a useable andpractical drillingm'u'd ,co'r'nprise the following: (1) initial gelstrength; (2) viscosity; (3) 18-minute gel strength; and (4) water loss,whichjjrelates to the sealing off of the wall of the drilling-hole bybuilding up a filter cake of mud on'thewall', thIJSQPIF venting loss ofwater from the mud. Thus, it is manifest that the drilling mud, with itsexacting requirements of various properties for the mud, is amostir'nportanhjnvolved, and complex feature of oil and gas welldrilling.

Universally, a drilling mud (having about the ctiirsistency oflubricating oil) is used in a circulating'systejfm with rotary welldrilling mechanism, and is ,forced'by pumping down the hollow drillstern through the bit which it lubricates and cools, then back to /thesurface toa settling pit. Thus it washes out the cuttings which havebeen made from the hole, and the cuttings are carried,

outside the drill stem to the surfacewhere the oo arseparticles arecaused to be removed and the mudagain used in a continuous circulatingvprocess. To prevent thejlpss 1 of the mud in porous strata, the mudmust be of aclrar acter to seal off such strata and the mud, its bystatic pressure, must prevent the escape of gas, prevent the well fromblowing out. To provide the proper hydrostatic pressure, the specificgravity of the ;mud

components of said sulfonated lignin-containingfmaterial may beincreased by adding heavierfmaterial than jclay, such as barytes. musthave the proper viscosity, that is, be thickenough to carry out thecuttings, but thin enough totbe pumped and to allow the coarse particlesto settle out inlthegsttrface mud pits so that the mud may be re-used. iOur invention and discovery is characterized by making it possible togreatly improve the effectiveness of the with very simple andinexpensive equipmentifiThe; friplicity of the treatment of ourinvention anddiscoveryf is one of its outstanding features. I l

One important property of drilling mud is thatin case of temporarystoppage of work, the'mud should gel. sufficiently to prevent settlingof the suspended cuttings, which settled cuttings would seize the drillstemand prevent re-starting or its withdrawal from the well. l-Trom thisit is manifest that the viscosity of the tfiuid is highly important.Likewise, the property to gel or to set like gelatin is important whenthe agitationincident to drill-* ing ceases. Thus, the mud will hold insuspensionthe cuttings and at the same time become fluid when ,agitationis resumed. This is called the thioxotropidproperty of the fluid, or itsgel strength. Most clay 's havethis property but not allj'Such propertymaybe in'creased H by'addin'g the clay called bentonite and similarsubstances. As the drilling proceeds throughdifferent strata; theviscosity and gel strength may be affected by the ch ac t'er of thestrata, by-the loss'by absorption of water porous strata or in theinflow of water and otlierliuids, by temperature changes, or bychemically activesubstances which may enter the drilling fluid'as' thedrilling proceeds; Accordingly, viscosity, gel and water loss are verycarefully watched and corrected from time to time during the drilling.There are instruments provided for testing such properties at the mouthof the well.

In the early history of well drilling, water was added to thin the mud,but this had the objectionable the 1s" On the other han'dthe drillingfluid nthe' ,the barytes which had been added to give weight.

of reducing the specific gravity of the drilling fluid and therebydecreased its hydrostatic pressure property, and also decreased itsability to suspend the cuttings and Also, to overcome the effect ofaddition of chemicals from the strata through which the well proceeded,i.e., the effect from so-called contaminants, other chemicals were addedto offset the deleterious effects.

In fact, the literature relating to drilling muds is so extensive andcomprehensive and has extended over such a long period of time that itis very apparent that important difficulties, mechanical, chemical andeconomical, are involved in the controlling, conditioning, and,obtaining of the proper type of drilling mud. It is one of thefundamental objects and purposes of this invention and discovery toprovide a drilling fluid containing an inexpensive and highly effectivemud additive to overcome the problems that have existed for so long inthis field. Let it always be kept in mind that the value of the drillingmud depends on how much it will contribute to speed, efiiciency, andsafety in oil and gas well drilling.

Our invention and discovery provides a combination of clay and treatedsulfonated lignin-containing material, which combination ischaracterized by its economy as well, as its very special effectiveness,not only for one of the two primary recognized types of drilling muds,i.e.,

, lime base and fresh water muds, but for the special effectiveness ofboth of said types of mud.

An important and fundamental object of our invention is to provide agypsum base mud characterized by a low gel rate rather than the usualobjectionable high gel rate .WhiCh is usually accompanied by high flatgels. muds accomplish the maintaining of suitable gels so that Suchcuttings fall out in the mud pit without the necessity of V wateringback to thin the mud. In this way, the need for costly water lossreducing agents such as carboxymetha contaminating character may heencountered in large masses which often supply calcium sulfate to thedrilling mud-this is very disadvantageous and alters or destroysrequired properties of the mud. Such calcium sulfate may be, among otherforms, in the form of gypsum (calcium sulfate with water ofcrystallization) and anhydrite (calcium sulfate without water ofcrystallization). The literature states (Rogers Composition andProperties of Oil Well Drilling Fluids, page 377):

The first small additions of calcium sulfate increase the viscosity andgel strength of the mud fluid greatly but do not increase the fluid lossappreciably. This peak portion of the viscosity curve is reached at anaddition of 33.3 ppm. calcium per gram of bentonite. As theconcentration of calcium sulfate increases, the viscosity 4 decreasesand the fluid loss increases sharply.

As the concentration of the calcium sulfate increases,

: the viscosity decreases and the fluid loss increases sharp-1y--obviously this feature evidences unpredictable character ofcontaminants upon the components of the drilling muds as respects theimportant properties which must characterize the mud. The differentproperties of the mud are affected differently.v Rogers states (saidtext, page 378):

unfortunately, the addition of the soluble sodium sulfate results in alarge increase in viscosity and gel strength. This effect is of such amagnitude that the method cannot be used in the field to overcome theadverse efiects of the anhydrite. It can, however, be demonstrated inthe laboratory.

The discovery and invention herein disclosed shows how thisobjectionable feature of sodium sulfate has been overcome, and to thisextent the invention, and dis- 4 covery of applicants is contrary to therecognized literature in this field.

Other contaminating strata are salt beds and the cement employed in theconstruction of the well. Also let it be noted that the contaminants maybe a combination of the contaminants disclosed herein.

It is the primary and fundamental purpose of our invention and discoveryto provide a drilling mud system or combination of clay and sulfonatedlignin containing material which will operate in controlling thecolloidal and physical properties and for maintaining the requiredproperties of a water-clay drilling mud which may be subject tocontaminants, so that the mud combination will function in a moreeffective and more economical manner than heretofore. Thus, an importantpart of our invention is the rendering more effective the properties ofthe sulfonated lignin containing materials and herein resides protectionagainst contamination.

This part of our invention relating to the sulfonated lignin containingmaterials is commonly referred to as the drilling mud additive. Ourpurpose is to provide such an additive of a character which willfunction as a control product for the colloidal and physical propertiesand for maintaining the required properties of the water clay drillingmud which may become subject to contaminants in the drilling operationand to provide such an additive when combined with the mud that willfunction in a more etficient and more economical manner than has beenaccomplished heretofore.

The part of our invention and discovery which relates to a furtherimprovement in lessening water loss of gypsum contaminated muds involvesthe addition of sodium sulfate or equivalents as hereinafter listed tothe combination of clayey material and the additive lignosulfonateproduct of our invention and discovery, in the proportion of 1% to 100%of said sodium sulfate or equivalents by Weight of the additivelignosulfonate product, said addition being made in proportionsdetermined by a pilot test of a drilling mud which is contaminated withcalcium sulfate. The additive product of our invention in and of itselfmay not produce the extremely low water losses desired in some muds. Theaddition of the sodium sulfate and equivalents as hereinafter listedwill further reduce the water loss to the desired level and at the sametime said additive product prevents the large rise in viscosity and gelfactors which occur when sodium sulfate alone is added to an aqueoussuspension of clayey material. Thus in the presence of the additivelignosulfonate product, the ordinary adverse action of the sodiumsulfate is depressed.

Sometimes the formations are of thick dolomitic lime or other rocksections which do not contribute good mud making materials. In suchcases it is necessary to control or maintain the mud by addition dailyof bentonite to develop the desired low fluid loss, and the pH of themud is maintained on the alkaline side to promote hydration anddispersion of the drilled shales. The alkaline pH promotes higherviscosities in the bentonite clays,

and, therefore, thinners are added and those with alkaline propertiessuch as the sodium tannate type are preferred. These thinners, becauseof the presence of alkaline sodium salt, aid in the formation of sodiumclays from the dispersed shales and also increase the degree ofdispersion of the clays and shales and hence reduce the fluid loss tostrata surrounding the hole. In general, the pH or alkalinity of suchmuds is maintained at about 9.0 or 10.0. At times the pH of the mudrises or is carried to the range of 10.5 to 11.5 in which the clays andbentonite I present manifest appreciably higher viscosity. Thetreatgasses more economical to convert to the .so-called vlime base mudrather than to dilute with waterinvolving the necessary addition ofweighting material. At .other times,

the contamination becomes so bad that the chemicals =-are not effectiveand it isfound necessary to convert to the lime base mud. Thisconversion involves the addition of an excess of lime and caustictogether with a thinner such as quebracho or, preferably,lignosulfonates. Thistype'of high pH m ud with an excess of lime is i",hereinafter referred to as a lime base mud as contrasted -,to all ofthe other water clay muds previously discussed, 1 which for conveniencewill behereinafter termed fresh ,watermuds.

uObjacta-In general, quebracho, as a thinner, has been used in all typesof muds, both fresh water and lime *base, but quebracho is an .expensivecommodity. To date,-the lignosulfonates have, been useful only in limebas'ernuds where they are wellknown to be relatively inexpensive-butuntil now, i.e., until the present invention, it has not-been possibletouse the lignosulfonates in the lower pH (less than 12, i.e., freshwater) muds .not containingan excess of lime, inasmuch as theylhave noappreciable thinninig action on such muds. One of ..the primary objectsof this invention is to provide a. drill- ;ing fluid compositioncontaining an additive comprising L -':a soluble sulfonatedlignin-containing material which is {highly effective, not only as limebase muds, but valso -.as fresh water type muds.

A primaryand fundamental object is to provide a drill- Ting fluidcontaining a dispersing agent derived from .spent wood pulping liquorsolids in the simplest and .most economical manner with relativelyinexpensive equipment, and in a continuous manner to produce from thesesaidliquor solids a soluble .additive for drilling mud systems orcombinations which isv effective in reducing the viscosity and gels ofboth fresh water muds. and

the so-called lime base muds,.even in the presence of substantial.quantities of natural contaminants suchv as -anhydrite, sodium chlorideand-sodium sulphate.

.Anotherobjective is to provide by a sequence of steps adrilling fluidcontaining an additive derived from spent wood pulping liquors which arepreferably initiallypurified and fractionated and then modified-toobtain a solu- .bleadditive. for making the mud combination of ourinventionwhich is characterized by the fact that molecules Of eachfraction are of a particular and different molecular average size andespeciallyuseful fordispersing .:agents in general and additives fordrilling muds in pari Another primary object of .our'invention is toprovide sentially all types of water clay and oil-in-water emulsiondrilling muds.

7 Still another object of this invention is to provide a drilling mudwhich is prepared with saline or sea water when fresh water is notreadilyavailable. Mud prepared :with sea water has special utility inoff-shore drilling where fresh water mustbe transported to the drillingsite and fresh water muds must be protected .fromsea watercontamination. We have found that the additive of our invention issurprisingly effective as a thinner not only for gypsumbase muds, butalso for saline muds :made up originally with sea water as the aqueouscom- .:ponent together with commercial drilling mud clays.

.Defining starting materials;Spent lignin liquors. from the pulping ofwood provide an inexpensive, source. of f fithe raw material forourprocess and.produc t the said iquorsfbeing availableinllargequantity. as wasteprod- -ucts of thepulping Processes. One of our aimsis to conserve this waste material.

The preferred raw material is derived from the pulping of wood by thecalcium bisulfite process for the manufacture of pulp. In this operationasubstantial portion (20% to 70%, usually about 55%) of the .wood isconverted to water soluble products which atthe end of the cookingprocess are separated from the'pulp in water solution. This solution,becauseof the washings, is very dilute, ranging approximately from 5 to20% solids. This solution can be used as such' inourprocess." or it canbe concentrated in any one of several well known ways to a moreconcentrated solution which is more readily and economically handled,parti'cularlybecause of the smaller volume of liquid involved. QIheconcentrated solution can range from 30% to70%,'but handles better inthe range of 40% to totalsolids in solution. This concentrationsolution'conta'ins lignosulfonates as salts (forexample calcium,magnesium, sodium, or ammonium salts, depending onwhich .ofthese areemployed in the digesting process); carbohydrates, I and other complexorganic compounds derived from.

wood, as well as inorganic compounds either present in the Wood orderived from the reaction. Furthermore, 5 I

digesting of wood by iron or aluminum bisulfite will; give a spentsulfite liquor component which mayfbe'ourfraw material and which willobviate the necessity of'a base exchange reaction to form/the iron oraluminum salts.

The concentrated solution may be used in our invention and it is verydesirable to do so. However, the spent sulfite liquor can be furtherrefined before or. after processing according to our invention.".Forexample, the

spent sulfite liquor-can be essentially freed of carbohy-- if:

drate material by any one of a number of .p r oedures, preferably byfermentation. may be removed by dialysis, by separation with organicsolvents or organic bases, or by precipitationas basic lignosulfonates,for example, with lime orby. salting out with salts such as calciumchloride or sodium chloride. In addition, the lignosulfonates, as wellas beingflfreed as far as possible of extraneous materials, may befractionated as to molecular weight components.

Any of these above d'escribed products are basically derived from spentsulfite liquor solids, and are sulfonated lignin-containing materialsand the degree of refining to which they are subjected either before orafter the steps of our invention will depend on the.,q11ality. .ofproduct desired and the economics involved. .That is, refining to someextent will improve theproperties of the final processed product, butthe degree of improvement will not always be economically justifiable.In fact, it isan essential and outstanding feature ofourinvention' anddiscovery that we can use concentratedspent' sulfite liquor as such, andthrough a series of simple steps involving equipment which is relativelyinexpensive, can

produce products which are equivalent in properties, for

instance, for use as drilling mud additives and dispersants, to thepurified lignosulfonates. J

In general, any type'of wood or lignocellulosicmaterial, the sameincluding straw, cor'nstalks, bagasse and the like, which can beresolved to pulp withthe separation of the lignin-containing material,maybe used as a source for providing lignosnlfonate in followingjourinvention. Furthermore-changes in the finalpropjer-tiesof the productare influenced by the conditions of the pulping process, but in generalgood results are obtained usingthe commercial spent sulfiteliquorffro'm'either' paper grade quality pulp or dissolving gradequality pulpi In addition to the spent sulfite liquorderived from theacid bisulfite pulping of wood, liquors containingsoluble lignin arealso availablefrom the neutral ,and alkaline pulping of wood or otherlignocellulosic material. Such lignin-containing materials may beconverted to sulfcnated lignin-containing materials usable. as raw ma 7Also, said carbohydrates "als 'for V the process of our invention, forinstance by treatment bound with the lignin as a sulfate. or sulfurcombined directly with carbon is a stably bound I with sulfites atelevated temperatures, chlorination and heating with sodium sulfite orby other methods known to those skilled in the art, subject only togetting. a soluble sulfonated lignin or one which tends to dissolve inwater and which on forming the metallic salt and being oxidized issoluble. For example and not by way of limitation, sulfonated kraftlignin has been found to perform well in making the oxidized metallicsalts of sulfonated lignin according to our disclosure. also true ofsulfonated soda lignin.

In deriving sulfonated lignin containing material from wood pulpingliquors varying degrees of sulfonated lignin-containing material result,depending on the well known range of conditions involved in thedifferent methods of sulfonation. For practicing our invention theresulting sulfonated raw material should be soluble in water or inhighly alkaline aqueous media and should have dispersing properties.These characteristics are in part associated with the degree ofsulfonation, or the proportion of sulfonic acid groups which haveentered the lignin molecule during the sulfonation process. The chemicalformula for sulfonic acid groups is --SO H, in which the sulfur atom iscombined directly with a carbon atom in the lignin or other organicmaterial in the lignin-containing material sulfonated.

This type of sulfur is to be distinguished from inorganic sulfates orsulfites, sulfur dioxide free or loosely combined with the lignin andsulfur which might be The sulfonate sulfur sulfur which is not removedfrom the lignin without drastic treatment such as with sodium hydroxideat high temperature and pressure. In speaking of the sulfur content ofthe sulfonated lignin-containing material, we refer to the total sulfuras the sulfur of all types which are deterwith the source of the ligninbeing sulfonated, i.e., the

conditions of pulping. However, sulfonated lignin, having sulfonatesulfur contents as low as those in the range 0.93.8% have been usedsuccessfully in making the dispersive additives of our invention.Products containing sulfonate sulfur in excess of these amounts do, ofcourse,

have the requisite solubility for use in accordance with the presentinvention.

By way of summary, the raw material for our process is a sulfonatedlignin-containing material as it may be received from the blow pit ofthe bisulfite process or modification of said bisulfite processemploying somewhat less acidity, for example and not limitation, aboutpH 4.5 instead of 1.5 or less, or other sulfonated lignincontainingmaterials such as those derived from neutral or alkaline pulpingprocesses. Any of these may be in any one of a number of states ordegrees of definement, purification and concentration. We prefer,however, to use concentrated and fermented spent sulfite liquor from thepulping of wood with calcium bisulfite cooking acid because suchmaterial is already sulfonated, and is easily converted to other metalsalts as disclosed hereinafter and is available in large quantities. Byfermented" is meant spent liquor from which carbohydrates have beenremoved by fermentation. In any event our starting material comprises asulfonated lignin-containing material.

Our starting material may be refined and fractionated, but whether it isfractionated before or after treatment according to our inventiondepends on economical considerations and the special product desired.

Briefly stated, our novel compositions include additives produced by aprocess which in part involves converting sulfonated lignin-containingmaterial to a salt of iron, chromium, copper, and aluminum, orcombinations of said salts; or converting the refined sulfonatedlignin-containing material to said salts; or converting the fraction-This is ated sulfonated lignin-containing material to said salts; or

converting to said metal salts sulfonated lignin material subjected toother pretreatments, effecting improvement in properties for use indrilling mud, for example but not by limitation, by alkaline heatpretreatment as set forth in our copending application Ser. No. 694,737,filed November 6, 1957, acid heat pretreatment, and pretreatment bysteam stripping, gas or air blowing during heating of solutions of saidsulfonated lignin-containing materials derived from spent wood pulpingliquors. Said acid treatment may be carried out at less than about pH 4at temperatures from C. to 180 C. for times causing polymerization orthickening of the solution short of gelation, as set forth in U.S.patent application Ser. No. 723,036, filed December 18, 1957, as acontinuationin-part of our U.S. patent application Serial No. 433,794,filed June 1, 1954, and Serial No. 539,542, filed October 10, 1955. Athigher pH, heating may be conducted at temperatures of 170 C. to 210 C.tobring about similar polymerization or thickening of the solution shortof gelation.

Another feature of the invention comprises the use of drilling fluidadditives prepared by a process which involves subjecting the sulfonatedlignin-containing material containing said metallic salts to oxidationwhich brings about changes in the constitution of the solids of thesulfonated lignin-containing material resulting in additives of greatlyenhanced properties comparable and superior to those of naturalquebracho in the making of drilling muds.

Also, liquor containing the said metallic salts of dissolvedfractionated components may be subjected to oxidation which bringsabout'changes in the constitution of the fractionated solids of thesulfonated lignin-containing materials resulting also in additives ofgreatly enhanced properties comparable and superior to those of naturalquebracho in making drilling muds. Our products are also superior indispersing the ingredients of clay slips, cement, plaster, etc.

The fact that the original spent sulfite liquor may be' oxidizeddirectly and converted to the said metallic salts, forming an additivewhich is effective in both fresh water and lime base muds, manifests howvery economical may be the products of our invention for such specialuses.

Another feature of the present invention comprises the use of drillingfluid additives prepared by a process which involves the oxidation ofsulfonated lignin-containing mamium of sulfite liquor which, for theproduction of an oxidized salt, can be done either before or afteroxidation, we prefer to use the sulfates of these elements for thispurpose because with calcium base sulfite liquor, calcium sulfateprecipitates so that it may be removed'and thereby bring aboutpurification of the product. Higher temperature promotes the growth oflarger crystals of calcium sulfate which are easier to separate from theliquor, hence it is desirable to hold the liquor after addition of thesulfate at -95 C. for a period of time. The formation of large crystalsis also fostered by bringing about the interaction of the salt with thespent sulfite liquor solids in such a manner that the precipitation ofthe calcium sulfate occurs more slowly. This objective can beaccomplished by using more dilute solutions and/ or using lowertemperatures during the base exchange reaction. Hence, a preferredmethod of forming the iron, chromium, copper, and aluminum salts is tocarry the um, and copper salts.

. teaction at '30-50 C. and then toheat the solutioniwith 7. during thisstage so that this latter treatmentis also an 1 acid treatment and hasbeneficialaction on the proper- 1 ties of the spentsulfite liquorproduct.

,- Aluminum sulfate may be added preferably in proportion equivalent tothe base (i.e., calcium, sodium, magnesium and ammonium) already presentin the spent sulvvfite liquor or it can be used in smaller or greaterproportions. Furthermore, aluminum sulfate may be added in anhydrousform or as any of the hydrates of commerce, such as paper makers alum(17% A1 or as Al (SO .1-8H O. In making the lignosulfonate'salts, Wehave used aluminum sulfate salts in the proportion of 1% to 50% byweight ofthe spent sulfite liquor solids. With the other salts-i.e.,iron, chromium and copper, the range of permissible addition is aboutthe same, i.e., 1% to 50%. For example, copper requires the addition ofabout 30% of CuSO .5H O'for complete base exchange as compared withabout 26% of Al (SO .18I-I O which takes into consideration the usualchemical equivalence.

. However, good results have been obtained in using from 15% to 30% ofaluminum sulfate (Al (SO .18H O) The same observation applies to the useof iron, chronn- In addition toadding suflicient' of the cations .to beequivalent to approximately the base present in the sulfonatedlignin-containing material, it is our unusual (and unexpected) discoverythat an excess of the cation over the chemical equivalent for baseexchange improves the effectiveness of the product of our invention anddiscovery, particularly in respect to they conditioning of fresh watermud in connection with obtaining the lowest possible values for yieldvalue and min. gel and water loss. Thus in the preparation offfreshwater muds, we prefer to add anlexcess of a sulfate salt having a cationselected from the group: iron, aluminum, copper and chromium, ormixtures thereof. Since these salts occur as hydrates with varyingamounts of Water, the permissible addition of these salts to the mud ismore definitely ex- I-pressed as an, amount of the sulfate saltequivalent to the anhydrous form of that salt..;'I-hus in terms of theanhydrous forms, the permissible addition is about 1% to 80% by weightof the sulfonated lignin, in excesszof "the amount of sulfate salt.necessary for the base exchange. Thus, forj'exampl'e, 'withathe ferricsulfate the optimum results are .obtained with a total addition of formin the same, manner and the excess addition over the chemical equivalenton' ananhydrous basis is also about. 1% to 80%. Mixtures of thesesulfate salts can beused for this purpose. Copper has the advantage ofimparting antiseptic properties to the additive, to preserve the mudWhich-may 'be subject to micro-biological atj-tack, particularly so whenstarch is present.

In regard to the permissible addition of excess sulfate :salt thedisclosure above ofl to 80% by weight of the anhydrous sulfate saltpertains to the salt and not to the oxidized salt. For the latter, thepermissible addition 'is somewhat less than 70% (see Table 3 of ExampleIX). Accordingly, from the standpoint of commercial practicability, asappliedto both the salt and the oxidized salt, --an" excess of'l to 50%of the anhydrous sulfate salt on the basis of the sulfonated: lignin. ispreferred.

In forming the said salts of the, sulfonated lignincontaining material,it is preferable to have the latter in the calcium condition, that is,as a calcium salt so that :when the sulfate salts of iron, aluminum,copper and chromium are added, the base exchange reaction ease-is andcalcium sulfate forms which can beremoved, thus yielding an essentiallypure form ofthe desired salt. I

This disclosure above relating to the permissible addition of 1 topertains particularly tosulfate salts, or any salt of said metals theanions of which form insoluble salts with calcium, for example,oxalates. How-' ever, any soluble salt of these metals could be added toa solution of the sulfonated lignin-containing material Without theformation and/or removal of a precipitate. The anion in said solublesalt may be any of the common anions such as, chloride, nitrate,formate', etc., although higher concentrations of chloride ions and to alesser extent nitrate ions become deleterious above theconcentrationequivalent to the base exchange capacity of the sulfonatedlignin. solution is brought to dryness, because of the ionic Continuingthen, when such a equilibrium in the solution, a mixture of salts isobtained. Thus, an amount of the desired lignosulfonate salt, forexample, iron, would be present in the product, together with the base(sodium, magnesium ammonium,

etc.) which was originally in the sulfonated lignin-con taining'material. This product would not be as ejfficient as the product inwhich the original base in the sulfonated 7 lignin-containing materialwas removed prior to or on addition of the iron salts. However, in-caseswhere-thesulfonated lignin-containingmaterial has-the base sodium,magnesium or ammonium present instead vof calcium, it

'may be satisfactory to make the partial salt in the aforesaid manner.This could be the case, for example, with sulfonated lignin from thekraft and soda processes which usually contains sodium .as the base byreason of theover and above the stoichiometric equivalent of thesulfonated lignin is added in preparing the product of our invention,and the added anions are not subsequently removed, a product is obtainedwhich is less efiicient as a thinner but nevertheless is effective. Thelower e-fficiency results from (1) dilution of the thinner by thesoluble inorganic salts, and (2) a thickening of the mud resulting fromthersmall amount of solubleinorganic, salt added to the. mud as acomponent of-the' thinner product. Thus, the thinner product with theexcess, appears to be ineflicient when used in small amounts but whenlarge amounts .of said thinner product is added to the mud,thesurprising resistance of the sulfonated lignin metal complex to thesalt contamination overcomes the 0 effect of the small amount ofinorganic salt.

The salt contamination effect maybe illustrated by consideringthecombination of one. part of ferric chloride with 2 parts by weight ofthinner additive of our invens tration in the mud approximatelyequivalent to 3 pounds per barrel of sodium chloride or about 1% of saidchloride and a thinner additive concentration of about 6 pounds perbarrel. A mud contaminated with 1% salt (sodium chloride) is readilythinned by 6 pounds per barrel of the thinner additive.

The amount of metal for complete base exchange will depend on theconcentration of acidic components in the sulfonated lignin-containingmaterial and in particular the-v concentration of the sulfonated lignin.Byway of example and not limitation fermented spent s'ulfi'te liquor--solids having a sulfone sulfur content'of about 6% will require about 5%of iron for base exchange. The addi tion of 50% excess anhydrous ferricsulfate over that re When magnesium, ammonium, or sodium bisulfite-Adding 9 pounds per barrel of this I combination to the drilling mudgives a chloride'con'cen- -cooking liquor instead ofccalcium has beenused in manufacturing the pulp, it is then desirable, but not absolutelynecessary, to eliminate or partially eliminate the magnesium, ammonium,or sodium ions prior to making the iron, chromium, copper, or aluminumsalt. This situation can be brought about by converting to the calciumsalt before proceeding with the process of our invention, or it can beaccomplished by any number of procedures well known to those skilled inthe artfor example, by ion exchange, dialysis with addition of acids,and base exchange procedures in general. For example, cations (i.e.,magnesium, ammonium, or sodium) may be re moved by passing the liquorthrough a cation exchange column in the hydrogen state, and then treatedwith an oxide or hydroxide of iron, chromium, copper or aluminum. Weprefer to have the lignosulfonate in the form of the calcium saltsbefore making the iron, chromium, copper, and aluminum salts because thesalts are obtained with less contamination in this manner by reason ofthe calcium sulfate being precipitated so it can be removedbut notewell, such purified products can be obtained by any procedure known tothe art for making the conversion to the desired salt as well as thosenamed immediately above.

An example of partial sa-lt formation comes as a result of the oxidationtreatment with sodium or potassium dichromate as a result of the factthat chromium salts are a product of the reactions involved. Any solublechromium salts thus formed will provide chromium ions which will be inequilibrium with the calcium ions associated with the sulfonate group ofthe lignosulfonate. Thus, a partial chromium salt of the lignosulfonatein essence will be formed which would tend to impart the propertiesattained if the calcium were removed and the lignosulfonate salt wereWholly chromium salts. I-f, furthermore, an excess over the amount ofsodium dichromate necessary for the base exchange, i.e., about 12% ofsodium dichromate, is added, additional chromium ions resulting from thereduction of the dichromate are present which tend to drive the reactionin the direction of the formation of the chromium salt of the liguosulfonate so that this excess would have somewhat the eifect of removingthe calcium or in other words, forming a chromium salt instead of thecalcium salt of the lignosulfonate. The addition of excess sodiumdichromate, would also result in an excess of chromium salts .formed bythe reduction of the dichromate and would have somewhat the effect ofthe addition of an excess of chromium sulfate over that necessary tomake the base exchange. This method of forming the salts, however, doesnot yield a product which is as effective for mud formulation as themethods previously described where calcium is removed, for example asthe sulfate or other wise, because calcium ions cause thickening ofdrilling mud and because of the miscellaneous reaction products.However, the effectiveness of agents made in this manner can be improvedby removing the calcium during the treatment, for example, by addingsulfuric acid or any other acid whose anion forms insoluble salts withcalcium or by addition of suitable salts which form insoluble compoundswith calcium such as sodium sulfate. This illustration is mentioned byway of example that an im provement can be obtained by the presence ofan excess of chromium, aluminum, copper, iron salts or combinationsthereof, even though there is an equilibrium mixture present with otherions, such as potassium and sodium, but is not given to indicate apreferred method of operation.

It should be noted that an excess of sodium ions resulting from excesssodium dichromate addition is not seriously harmful since the drillingmud clays are the lignosulfonates thus formed are useful as drilling 12mud thinners in muds which do not contain an excess of lime, i.e., freshwater muds, and these products are thereby distinguished from the spentsulfite liquor products previously used as thinners in the so-ealledlime base muds. These previous lignosulfonate thinners which may beammonium, sodium, magnesium, or calcium salts of lignosulfonates areoperable only in the lime base muds and are not effective in muds whichare sometimes termed fresh water muds, i.e., muds of low pH and which donot contain salts of aluminum, iron, copper and chromiumthe inclusion ofsaid salts being a part of our invention and discovery. The aluminum,iron, copper, and chromium salts of the spent sulfite liquor on theother hand are effective in varying degrees over the whole pH range ofthe fresh water muds and are also operable as thinners in lime basemuds.

Furthermore, let it be noted that another alternate pretreatment may beused whereby the hot spent sulfite liquor is acidified and air blown ortreated to remove the sulfur dioxide and then oxidized with the agentsdescribed below. By this course the spent sulfite liquor is purified ofsulfur dioxide, and apparently the structure of the components of thespent sulfite liquor is modified and the oxidizing agents if later usedare conserved for performing their special functions.

As heretofore indicated an important feature of our invention anddiscovery is that the oxidation of spent sulfite liquor components leadsto increased activity or enhanced properties of said componentsrespecting dispersing properties, and that these changed properties aremanifested in the thinning of the viscosity of clay suspensions and alsoin the reduction of the gel-like properties of such suspensions. We havefound that most oxidizing agents are operable in varying degrees as tothe improvement produced. Particularly effective for this purpose arethe following: hydrogen peroxide, ozone, lead dioxide, chromic acid,chlorine, alkali and alkaline earth hypochlorites, alkali metalchromate, alkali metal permanganate, alkali metal persulfate, alkalimetal perborate, and electrolytic oxidation. These several agents arethe preferred oxidizing agents.

The preferred forms of the oxidizing salts such as chromates,permanganates and persulfates are the sodium and potassium salts, butthe ammonium salts may also be used and where available are included inthe descriptive term alkali metal salts.

When chromate is used for oxidation of spent sulfite liquor, thechromate is added preferably as sodium dichromate, since this form isthe most readily available in commerce, and in subsequent discussionsthe chromate addition is referred to as dichromate. However, it is wellknown that in aqueous solution chromate ions (CI'O4 and dichromate ions(C1'2O7 are readily interconvertible, depending on the pH of thesolution. In strongly acid solution, the dichromate ion predominates,but on neutralization with alkali the dichromate shifts to the chromate.Equilibrium is readily reached between the two forms, depending on thepH of the solution. Therefore the chromate may be added as eitherchromate or dichromate.

Further in regard to oxidation with chromium compounds: By experiment,we have discovered that oxidation of fermented spent sulfite liquorsolids with sodium chromate at pH 8 provides a product which hassubstantially the same thinning effect on the drilling mud as a productobtained by oxidation with sodium dichromate at pH 4. In making thisexperiment both products were converted to the iron salt to make the mudtest. Furthermore chromic acid may be used instead of the chromates inwhich case it is usually necessary to add sodium hydroxide to neutralizethe product to about pH 4 to 5 prior to drying. All of these chemicals,i.e., sodium chromate, sodium dichromate and chromic acid give oxidizedproducts, the iron, aluminum, copper and chromium salts of ofthe so meatth nn s o b hl me andresh Wate muds and give substantially similarresults.

Qne method of obtaining oxidation is by electrolysis yvhereby oxidationtakes place. at the anode of an elec- .trolytic cell. We have found thateifective electrolysis can be obtained in a simple cell with or withouta mem- .-brane to separate the anode and cathode, and improved productshave been obtained with current usages from .a desired efiectiveamountup to about ampere hours or more per gram of, sulfonatedlignin-containing matelt will bennderstood that the amount of impuritiesor oontaminants,'including carbohydrates andsulfur di- 1 I guide, in thesulf onated:lignin-containing material eleczed, will rehange theelectrical current consumption amperes hours. per gram of saidsulfonated'mateto'obtain a givendesired result. Thus wehave found thatfrom about 02: to 5.0 ampere hours per is s itable for ermen ed s ent sufi e l q bu ess e re eeneume e l e h e e fe me e Pufifie .sul-fonatedmaterial while greater current consumption may be necessary for lesspurified sulfonated lig ninee ta ih m e he el tr y o l b e hd e e u de entl ieh I w liehw l bring abeut t o -and ne eduet h- F 8 pur e e at eeaet ef-an de. t s an ene e whmhdoes not dissolve substantially duringthe electrolysis lshould be used. Thus platinum is suitable- Also,

i is preferab e to ar y n'-. e e eetrel t e exi lati pr or to fo m n a ine fe e salt. ef the meta iro pp d omium H er. he a is ormedeetr y s nyieta 19 iq examp y Plating n t c hode uld sbe e eed, at

the equivalent ofsuch lost metal should he readded to the electrolyzedsolution. This loss of metal ions may be sub tan ial y e i in ted'hyeleetrelyzing und ae deenrs i n o be ow b ut P 3, o s tated bo by e ee-.trolyzing before forming the said salt. 4

Oxidation by addition of sodium perborate results in contamination ofthe'product with sodium borate which must be removed to obtain thegreatest eificiency of the product. One method of purifying the productis to remoyethe resulting horate ions as calcium borate which e dily-oct t ng m t n' l i aca' i msal of ulfsi at l gni rcent in g mat al hesodium-n rbora e hasg u' kah er e i n a a es the a ka i ity lu onsufiici'ently to make calcium borate insolublevifh ealeiuin horate m y bmoved y filter- --ing orisettling. Other methods known to those skilledin the art can be usedfor such purification. As set forth herein,chlorination also. results in by-produots of the reaction which shouldbe removed by purification to; ob-

tain more efiective products for drilling mud thinning.

In regard to the choice and use of'oxidizing agentsfor practicing ourinvention, two factorsv are. of prime .im-

,portance: The strength or; power: of the oxidizing agent and thequantity of oxidant being used in proportion. to

the organic solids being oxidized. The strength or in- ,tensityiof'theoxidizing agent is expressed as an oxidationdeduction potential, andtables of thesepotentials are..-

available in the chemical literature. We havefound that the; oxidizingagents which areisuitable for carrying out our, inventionhave a range ofonidation potentials greater than, 7,-1.3. The quantity ofoxidant whichis usedv to bring about the desired result may be expressed as theweight in grams of each oxidant which can be. used per 190; grams ofsulfonated lignin-containing material.

' Fhe amount of oxidantirequireddepends on thespecific" oxidant beingused, thenature and purity of the sulfonated lignin-containing materialbeing treated and the conditions under which ,the treatments areconducted. In. gen ral j' er p a i op rat o p tic y. e.-

.'-.-,spec ting'cost,-1 to 50 by weight of the several" oxidants on thebasis of the dry su lfonated lignin-contain -ipg matqrial is all that sr ir d e-P e bee e-des red 'Heue ee'vt eh the. oxidant s; et; a.eseeneeswei h tin sth le se of al a rets l at and tionshouldlbeconducted in such amanner co eentrations and proportions of themeactants7 at=.gelation of thesolution does .not occur and a a permanently Isoluble product is obtained. Solubility of nur additive product is afundamental requirement because-the produetlis to be added to a drillingmud system, one component of which is water in which the additive.productn ust dissolve .to function as a thinner-L. Also, "thedissolving brings about the. distribution of the agent unito mlythroughout .the'medium which increases the sliceamen out-t e Product.

By way of "xplanation gels contain some occluded w l r-soluble productand to the extent that the water soluble component is available or theygel.- dissolvedin. the medium s 'd.g els'function shmew'hat as thinners..If any .thi nnin'g ac" n-occurs with gelled (i.e insolubleyprod- Vucts, such is deemed not to be due to the gel iunetieaing a a surfaceactive agent but isidue t soluble component accompanying the gel. Athigherp abuse. a ohtfla the hnwa h d' p ducts dissolv to sgmedegree andshow some tendency to thin the mud.

Partic lar y is th sv me .if-l i d ssol ed component s not washed out.'In any case gels are not desirablebee eause th m eria istless. .eifieent-V I I Permanently st ble sol ns u e t ne shown intheexarpples may beobtained by conditions which s ow. the rate of reac on a k ep thereactants i W e neeatra 1. i n to ch other. other eondltions a g theformation of gels 'in more or les e ree ar th de r o ut on, hncentereaxtign of flag splfom @(1 ligni'n conta n m t erat re e9 ationof h oxidant, PH d ee iy iiess, of-nnxi g. In addition, the character ofthe'fsiilfonated, lignin containing material beingLtreated-afiects theamount of oxidant being used, in particular, the degreetoWhiGhihQ mateal ha n previously p f ed, especially of ueing substance such as sulfurdio de and eerbehydra es, a d fractionated- T e d lfi? Qi Sllionationimportant in regard to water solubility. 0, we have discovered thatthe.molecular f apparently the molecular weight distribu'- tion within thefraction will aifcct the quantity of oxidant required to. bring aboutthe desired result. B y

' .tion, when a caustic treatedfermented spent sulfite liquor bed inExample XIV is used at pH 4, about- 8% of sod dichromate'will causegelation at 42% total ,fermented spent sulfite liquor solids, of sodiumdichromatewill causergelling at solids and'21% of r 'sodiumgdichromate,at, 12% total solidsythe dichromate in eachcase being added as a 25%solution inwater at G. Let it be noted that the above percentages arebased on the Weight of the dried fermented spent sulfite liquorsolids'being treated. Moreover under other conditions, even more of thisoxidant can be added without v causing permanent gelation or loss ofwater solubility.

Purification and molecular weight are other factors which bring aboutgelation with difierent proportions of the For example, using a solutionof to oxidant. total solids, about. 4% by weight of the solids of theoxidant-will gel. the purified high molecularvweight lignosulfonatesat;a pH of; less than 4.5, whereas, as much as; 8% or meresqip tass umtP ans n e o s um 1?, U be n stl a l g p en age of-isueh yg idantis eqired to obtain the desired result. :In any dichromate may be added tothe low molecular weight lignosulfonate fractions of the sameconcentration without gelation. But substantially larger concentrationsof sodium or potassium dichromate may be added if the reactants aredilute. For example, a low molecular weight lignosulfonate fraction (40%of the total original fermented spent sulfite liquor solids) containing17% of reducing substances expressed as glucose as a 2.5% solution inwater treated at room temperature with 50% by weight of sodiumdichromate as a 2.5% solution at a pH of 3 yielded after drying at roomtemperature a product which was slowly soluble in water. With 40% byweight of sodium dichromate the product was rapidly soluble in water.During such reactions the pH rises and acid such as sulfuric may beadded to maintain the desired pH. The reaction under the aboveconditions was substantially complete in one hour. Thus the objective,namely a water soluble oxidized product, can be obtained with up to 50%by weight of the dichromate oxidant depending on the conditions used inthe reaction. Similar results are obtained with potassium and sodiumpermanganate. The other oxidants which are less subject to providinginsoluble products may also be 'used up to 50% and more by weight of thesulfonated lignin-containing material depending upon said conditions.

Pilot tests.We have discovered that the oxidants whichare suitable foroxidizing the sulfonated lignincontaining material may be roughlydivided into two groups: Those containing the metal ions chromium andmanganese, i.e., the alkali metal chromates and thealkali metalpermanganates and those involving gaseous oxidation components, such ashydrogen peroxide, sodium persulfate, sodium perborate and chlorine and,accordingly, different tests were originally necessary in establishingthe maximum amount of the oxidant which could be used for any particularsulfonated lignin containing material.

The maximum amount of oxidant particularly the chromates andpermanganates which can be used with any one sulfonated ligm'ncontaining material can be determined by the following pilot test. Adissolved sample of the sulfonated lignin containing material is dilutedto 2.5% solids, acidified to pH 3.0 with ,sulfuric acid for thisparticular test and various amounts of sodium dichromate added, togetherwith sulfuric acid to maintain pH 3.0. The solutions are then allowed tostand about 1 hour at room temperature, adding sulfuric acid atintervals to maintain pH 3.0. At the end of 1 hour, the sample is heatedto 80 to 90 C. and digested at this temperature for about an hour. Theproduct samples are then dried at 60 C. and tested for solubility inwater. The highest amount of dichromate giving a soluble product is themaximum limit of the amount of oxidant that can be used.

Another guiding test as to the maximum quantity of oxidant which may beused with any one sulfonated lignin containing material in forming theproducts of our invention and discovery is an evaluation of theperformance of the product as a thinning agent for drilling mud. T applythis test, a solution of about 10 grams of sulfonated lignin containingmaterial dissolved in 10 cc. of water is treated with 2 grams of ferricsulfate to convert the lignosulfonate to the iron salt, the solutionheated to 80 C. and centrifuged to remove calcium sulfate. This solutionis then treated with various amounts of the oxidant being tested at a pHof about 3 to 5 for this particular experiment and heated at 8090 C. forabout 1 hour and then dried at 60 C. The product is tested forsolubility in water, as above, and then for mud thinning properties asdescribed herein. If the properties of the base mud are not improved bythe addition of the product, then too high a. concentration of thatparticular oxidant was used in the oxidation 7 stage.

In using the oxidizing agents which evolve a gas in the oxidationprocess, such as hydrogen peroxide, chlorine or sodium persulfate, agreater amount than that equivalent to sodium dichromate or sodiumpermanganate is required, since the use of such agents involves a morerapid deterioration and possible escapement of gas withof oxygen thatcan be used, they are not exactly equivalent in regard to theimprovement which equivalent amounts of each of the oxidants willproduce in the product.

Optimum thinning properties appear to be attained with sodium dichromateusages which give solutions well removed from the point of gelation. Fora fermented spent sulfite liquor, of 40% to 45% total solids, thepreferred amount of oxidant is about 7% to 9% of sodium dichromate basedon the spent sulfite liquor solids for overall performance respectingthe several properties required in drilling mud, but especially lowwater loss characteristics have been observed with about 18% of sodiumdichromate. 0n the other hand, with chlorine which is considered anoxidizing agent herein, substantially more than the other agents can beadded because some of the chlorine reacts by substitution with the spentsulfite liquor components, so that additional chlorine is required tobring about the desired oxidation results.

The time and temperature of the reaction is important in that thereaction should be allowed to go essentially to completion and theproduct should be substantially free of gels. It is preferable that theoxidation be controlled to yield a solution which can be dried to apowder which can be redissolved in water. If the oxidation is too severethe solution may gel or the dried solids may not be water soluble.Potassium permanganate and potassium dichromate are very rapid in theiraction and usually the oxidation is complete in 5 to 20 minutes andthereafter the solution is stable and shows no visible evidence ofchange on standing. If 10% of these agents are added as a 25% solutionto concentrated liquor of greater than 40%, the spent sulfite liquorwill gel in 15 minutes at room temperature, or if the solution is hot,the gelation will occur almost immediately. Solutions more dilute inorganic solids, permit the addition of higher percentages of theseoxidants. With milder oxidants, such as hydrogen peroxide, 15 minutes to24 hours are necessary to bring about the completion of the oxidation.The temperature is usually a matter of choice and convenience but shouldbe such that the reaction is complete in the time provided, althoughlower temperatures will give less difiiculty with local formation ofgels.

The concentration of the spent sulfite liquor can be any concentrationup to 70% by weight of solids, but it is de sirable to have theconcentration of the liquor low enough to promote homogeneous reactionand prevent subsequent gelation. However, for practical reasons, it ispreferred to use solutions of as high concentration as possible and,preferably, of the order of 40 to 50% solids concentration. For thisreason, the dilute solution of the oxidant is added to the cool spentsulfite liquor solution of 40 to 50% solids with intensive mixing andafter the reaction has been more or less completed, the solution isheated to the temperature at which drying will be conducted.

Thus, it is clear that, because of the choice of oxidants involved inproviding required properties, the varied-nature of the sulfonatedlignin containing material, and the many factors involved in thephysical conditions under which the reactions can be conducted, and alsothe many well known types of equipment used in mixing t e reactants,that it is not feasible to set forth the exact 7 17 operating"conditions for each roduct of prod"" Furthermore, the-factor of what"mud" property is'm'ost d'esired' must be considered" since theproperties' do not respond in a parallel manner to all treatments. Thatis,

sometimes all-the properties may be improved whereas insome casesonlyoneof the properties may be improved. Accordingly, a--- selectionmust bemade to obtain thede sired result. But many eiiain riles aregivenin the herein disclosure? which will enable persons skilled iri the artto sel'ect 'conditions of=' treatment-best suited to theparticularrequirement of the case in hand. But for most cases for use in thefield-the oxidants can berused in the concentration of l'to 50% byweight" of" the organic solids as:- herein disclosed and thereby obtaina fully reacted and soluble product without gelation. The determinationV (of the maximum amount of any given oxidant which can beused-for anyparticular sulfonated lignin-co'ntaining material is determined by pilottests as hereinbefore described; But-the usage isone depending: uponwhich I mud property; is most-i desired;

Special-processingis -necessary when chlorine is used as the oxidizing:agent since in addition to oxidation' and any other reactions whichoccur; there is a reaction of chlorine with thesulfite-liquorcomponents, and there are I by-products-from-the reaction such ashydrochloric acid,

is to'precipitate thechlorinate'chligiim W; h lim treatm nnhasadditionalbenefit off urifying 1th l gn'o; sulfonates not'only of th'e'hydrochloric acid and its' end products, butfalsoof-the" carbohydratesthemselves; In this connection we have discovered that, Whereas withregular" spent sulfite" liquorfit" is difiicult" to divide" the lignosulfonates' into several fractions by treatment with Y lime,surprisingly withthe chlorinated lign'ins' of' our in vention' anddiscover, the products" can be divided very readily into" fractions ofdifier'ent" average molecular weight. This findinghas been of extremeusefulness in the preparation ofspecific fractions of the chlorinatedlignin as to molecularweight;

It has been knowrrthat lignos'ulfonates' maybe"precipitated in mass fromspent'sulfite liquor by adding atonef time" relatively-'large'quantities of' lime slurry'until a pH of 1 1 12is'reacl1'edf It"is ourdisco'very thatthe' ligno sulfonate can be precipitated. andrecovered as fractions of diiferentmolecularweightsby' addin'gth'e' limein' small increments. Especially"surprising 'and'usefulisour'diso'ui"i'nvention comprehends the discovery r'i withorwith'out' forming a saltof a' metal selected fromthe group of: iron, aluminum, copper andchromium ofthe lignin sulfonate-containing material provides an improveddrilling fluidi and that the amount of o hdat'ioh can "be" g're'atlyvaried.

Th xidiz'edprdducts a e useful asthinners, and this is par ula'rlyimportanflbecause products can be prepared neni the-original spentsulfit'e liquor merely by a simple oxidation process to give product sequivalent as thinners to those prepar'ed by more complex and expensivepieced-1n Furthermore; let it be particularly noted -essential y inprecipitation 1 andfractionation procedures' only" apart of the-spentsulfiteliquor'solids are available I for. use-as rri'ud'thinners while,in contrast, our

inventioif and discovery use'fof substantially all of ThlS point 1simportant where yield andj such solids: N W I I costs are of primeconsideration.

Iii genera-l; thejproducts: of our invention and discovery rfia ybeprepar'e'd from spent pulping liquor and the solids therein in thecondition as received directly "from the di g'ester," orsaid pro'duct'smay beprepared .from modifications of the said solid components of thespent pulpir'tg l-iquoii Suchmodifications may be provided by varioustreatments but, nevertheless, the resulting solids still do constitutesoluble sulfonated lignin' containing materials, By way of example andnot limitation the treated solids may 'be" as follows: They may be" asthey existaft'er fermentation-of spent sulfite liquor whereby thecarbohydrate c'onten't-is reduced or they maybe as so d's after hot"spent sulfite liquor is acidified'andan states the spent sulfite liquortreated with an l hydroxide; indem the's'ame may be heated t CI fora-period offifl r'riiriutes to 2weeks, 'orgzinic components beingmaintained in solu'* tion throughout the said reaction period; or'thespent sulfite liquor may be essentially freed-of carbohydrates andextraneous materialbyariyi one-ofa'fiumber of procedures,preferablyby'ferinentatiomorby adding increments of lime, a orbyprecipitation dialysis; 5 separation by organic; solvents, and/0rorganic bases, or precipita was basic 'lignosulfonate'ifor' example'with lime, or p have been derived by the pulping with agentsotherth'a'n' theusuafmag'nesium; sodium, ammonium, and calciumbisulfites. These other agents disclosed herein are iron andalnminumbisnlfit'es'.

Oxidation treatment improves the spentsulfite liquor componentsin'providing a' more effectiveilinie mud? thin covery that if thelignosulfonates are treated with chlo'-' rine thenthey may bemorere'adily divided by. lime *precipitation into 'many small fractions,while'at the same time purifying the 'li gnosulfonates from thecarbohydrates,

chlorides, and other miscellaneous components of thesiilthe liquor. Theoxidized and-chlorinated lignosulfonates, fractionated as tomolecular'weight by lime, may then be used as such as lime base mudthinners; or they'm'aybe convertedto aluminum, iron, copper, andchromiumfsalts and as such'th'eyalsdmalge highly eifectiveffresh'w'aterf such oxidized and chlorinated drilling mud thinners;lignosulfonates may be converted to other salts such" as sodium,magnesium, ammonium, etc., if calcium isobjectionablein' theproductl'Fractionation of the'chlorinat'e'd spent sulfite liquor can also beaccomplished by" the alcohol fractienation roeess' aocordifig td 'thedisclosures of our application- Serial No;'-'437;833.

ne'r orrnore eifect'ive' thinning and dispersing. action in general;i.e.', in both linie base and fresh water muds.

Base exchange tdftirrn' iron, aluminum, chromium, or copper saltsenhances fresh water mud thinning'propcities, and improves some or thelimemud properties, as for example a base'exchange withalurninumsulfatewill yield a'product with" lower viscosity'and gel char aeteri'stics' inlimefmud'. i

Up as this point the disclosure has; dealtpn'marily and especially withthe treatment of the spent sulfite liquor components and with theirfractionation,- their treatmentwith metallicis'alt's', and the oxidationof said Components, as vvell as with the use of such spent'sulfiteliquor 'coinpon'ent'sinpreparing well drilling muds in generahine'stablishing or proving first; that a change is made in saidcdrriporfentsby the treatment of our 'invern: tion" and discovery, and,second, that the magnitude of the change is surprisinglyi great, asevidenced by'the in crease'd" and aug'rnent'edfeiiectivenes's' of thetreated com! vn oifthey mayfbe obtainedas sef'fortlilin p'licatioir'Sei. No;'391-,=1l6, now-"abandoned; which briefly 'as revealed in -thepreparation "of'such drilling" Now the disclosure will relate morespecifically to the particular use of the said components in providing aproduct for controlling the colloidal and physical properties of gypsumbase drilling muds so as to maintain them in the most desirablecondition for use.

As one application of our invention we provide for muds wherecontamination is encountered from calcium sulfate (either as so-calledgyp, or in the anhydrite form, Portland cement, and similar calciumbearing material which would supply calcium ions which flocculate sodiumbentonite as calcium bentonite through base exchange reaction. Thisflocculation of the bentonite resultsin an increase in the mud waterloss. The water loss value of the drilling fluid may be 8 cc. at thetime of entering a massive anhydrite section and 24 hours later beanywhere from 25 to 75 cc. if the mud is not treated properly. Anhydriteand cement differ in that the former supplies the sulfate radical alongwith the calcium while the latter supplies the hydroxyl radical whichincreases the fluid pH. The sulfate radical does not affect the pH ofthe solution although the pH of the mud may drop slightly throughreplacement of the hydrogen ions from the bentonite particle by thecalcium. The net effect of the drilling of sufficient anhydrite tosaturate the mud aqueous phase with calcium is first to result in amarked increase of gel strength followed by a gradual increase in thewater loss as the bentonite is converted to the calcium bentonite. Asthe calcium bentonite flocculates through loss of hydration properties,the gel strength decreases. The final result is a mud of high waterloss, low viscosity and low gel strength. (P. 25, Composition andProperties of Oil Well Drilling Muds, Rogers, Rev. Ed.)

In case of contamination with calcium bearing strata, Rogers furtherstates (beginning on p. 379 of said text):

The precipitation and removal of calcium from solution can beaccomplished by at least four chemicals. These are:

(1) Bentonite (2) Soda ash (Na CO (3) Disodium phosphate (Na HPO (4)Barium carbonate (BaCO The first, the use of bentonite, is not veryeflicient but has been used in drilling anhydrite together with largequantities of thinners. It is not recommended for large quantities ofcalcium sulfate and will not be discussed further.

Soda ash is a common chemical precipitant for calcium sulfate. Thereaction is:

In this reaction the calcium is precipitated as calcium carbonate whilesoluble sodium sulfate is formed and remains in solution. In thisreaction 1.0 pounds of soda ash will precipitate 1.283 pounds of calciumsulfate. The reaction goes to completion and excess quantities of sodaash are not required. The method has two disadvantages. The firstresults from high pH of soda ash. The compound in strong solution has apH of approximately 11.2. The action of high pH in gelling bentonitemixtures has been shown previously. Since the pH of the mud willincrease greatly from excess soda ash it is usually cutomary to use SAPPas a thinner because of its low pH value. The second disadvantageresults from the continuing accumulation of sodium sulfate as calciumcarbonate is precipitated. Any increase in concentration of such solublesalts acts to increase the gel strength. One of the main difiicultieswith the soda ash treatment where thick beds of anhydrite areencountered is that the development of high gel strength from increasedmud pH and sodium sulfate formation is so extensive that soda ashadditions have to lag additions of thinner to reduce the mud pH and gelstrength. As a result the calcium contamination continues to gain andthe fluid loss continues to rise. It has been found impossible tomaintain fluid-loss values below 15 cc. when using this treating methodto drill massive anhydrite. Where the contami nation consists ofstringers of short duration, soda ash can be used to handle anhydritesatisfactorily as its ex tent is not sufficient to allow accumulation ofsodium sulfate or the high pH condition.

Disodium phosphate as a chemical precipitant for calcium sulfate issimilar in many respects to soda ash. The reaction with anhydrite is:

3 a HP 04-9 C213 P 04) 2-2N32S04H2SO4 The products of the reaction arecalcium phosphate, which precipitates from solution, and sodium sulfateand sulfuric acid which remain behind as soluble constituents. In thisreaction 1.0 pound of disodium phosphate will precipitate 1.430 poundsof calcium sulfate. While disodium phosphate is slightly more eflicient,pound for pound, as a precipitant for calcium sulfate that is soda ash,its greater cost is a deterrent to its use for this purpose. Thesimilarity with soda ash results from the single precipitation of thecalcium with sodium sulfate as a residue. The divergence is largely inthe pH difference of the two compounds. Disodium phosphate has a pH instrong aqueous solution of 8.6. The addition of this mildly alkalinecompound to the mud does not result in as high gel strengths as obtainedfrom soda ash. The residual quantities of sodium sulfate and acid act toincrease the viscosity and gel strength of the mud. There are no data inthe literature covering case histories of massive anhydrite drilled withthis compound.

Barium carbonate makes a satisfactory chemical precipitant when drillingmassive anhydrite. The reaction is:

CaSO --BaCO CaCO --BaSO In some respects this treatment is superior tothat of soda ash or disodium phosphate. This results from the completeprecipitation of both the calcium and the sulfate radicals of theanhydrite as well as the barium and the carbonate of the treatment,leaving no soluble salts in solution. The barium carbonate isapproximately neutral in pH and allows the mud to be restored to itsoriginal condition and allows lot fluid losses and viscosities to bemaintained while drilling anhydrite. The principal disadvantage of themethod lies in the large quantities of material required and theresulting high cost. 1.0 pound of barium carbonate will precipitate only0.691 pound of calcium sulfate. In addition, the reaction is not veryeflicient as more barium carbonate must be used then called for by thereaction. Fortunately the addition of excess quantities of bariumcarbonate does not affect the mud adversely and over-treatment isprimarily undesirable because of the cost of the barium carbonate sowasted.

Thus, all these methods of overcoming the contaminant calcium sulfatefail, or are objectionable for one reason or another.

By way of summary, it may be stated that presently three methods oftreatment are commonly used in the field to overcome the deleteriouseffect of calcium sulfate:

(1) One method is to convert the mud to a limed mud by adding 3 to 5pounds per barrel (a barrel being about 400 pounds) of hydrated lime, 1%pounds per barrel of tannin, or 2% to.3 /z pounds per barrel of calciumlignosulfonate and then adding carboxymethyl cellulose and starch tocontrol water loss. This method is expensive.

(2) Another method used is the employment of high pH red mud. The mud israised to about pH 12 with equal parts of caustic and tannin, and waterloss is controlled by addition of carboxymethyl cellulose. This methodis also objectionable because it is expensive.

elf.

, :t-fil Ashirdmethod;.andhiabahlyaheanostcommunly used; convert. it agypsum base mud,- byl-adding ;3. to 40119. synsuin 12erh-arre pof .mud.The mud ,..is

nod :thtthe es re viscos y with water, and. .4 to

- .s s .;and s tel/ pounds arr lnf .a prese vative added-to prev ntfermen ation thesta s This objectionable be ause of, the .h sh afl t:n esawhl h zma sethe mud ha d-to pump eenwellsandma t difficult for.cuttings to epatatei a the su f ce mud-nus.

' Furthermore, by adding water, the volume of the mud is increased, andtherefore part of themud must be1dis-.. carded to accommodate thecapacity. of ithe iequipinent.

Also, because of the addition of watergthe density of=--the I mud isdecreased and additional expensive weightinglmaterial must be added toincrease the weight of'the mud for-deep drilling.

One of the outstanding features of using the product of our inventionand discovery, in preparing drilling {muds is to provide a method ofcontrolling mud properties against contaminants in drilling calciumsulfate bearing strata which is less expensive and requires a minimum ofeffort and attention at the time such-,a stratum isencontaminants isanticipated. In .fact, as shown by Example XV, it may be only necessaryto add 3 to 4 pounds per barrel of additional conditioner to the mudbeing used in the well at the time .the anhydrite is approached. N.B.Our product-is particularly relatively inexpensive,

A further outstanding feature of the use of the product, of ourinvention is the providing of a gypsum base mud countered in thedrilling, or when contamination by with a low gel ratethat is, a mudwith n low initial gel strength so that cuttings will settle ous-and beremoved while the mud is flowing to and circulating in the mud pit,

u but with asufiiciently higligel strength in the quiescent state sothat sand and cuttings will-notsettle out in the well if drillingoperations are temporarily interrupted for a period of time. Heretofore,gypsum base muds-in common use have had high fiat gelsfthat is, highinitial and final gels. The viscosityof these muds increased as sand andfine cuttings. accumulated, and ,it was necessary to maintain lowviscosity by discarding some of the mud andbringing the remainder'up tovolume with'watera'nd bentonite. This treatment raised the water lossand it was necessary to add starch and carboxymethyl cellulose,

-which are expensive, to maintain a low water loss. By

usingamud as in .this 'invention,. with a low' initial gel strengthwithoubwatering-back, that is, the addition of more water, the cuttingsnevertheless doisettle out in the base-muds, haveveryfdesirable drillingmud properties & .I1d.-3 the:highcalciunrion content of these muds is.in reducing the hydration of certain shales en-v .d-in oilwelldrilling.Thisyprevents the shales court V f m swelling and closing the bore holeandthe shale cuttingsqfrom making an excessive amount of thick mud.

I Another desirable feature of our gypsum base muds is their thermal;stability, a property essential for drilling deep wells in which hightemperatures are encountered.

Il snmud of our inven on r cha-raet r ed y their.

th m-e1 stabi ty atdeepi ell temperature r A further important featureof the useof out-products o'r- -additiues. is;foundin; providing -a mudresistant to gyp: sumscontamination,"which may be. converted to oilemulsion mud. H v

another outstanding characteristicof.the'use-ofthe- Ilwductstor'additivessof tour invention5..and. discovery is found in the.providinggener-ally of muds with goodzthermal stability for drillingdcepwells where high temperatures are encountered. Temperatures can veryseriously affect he ec ssary properties of v the drilling mud-land thereitis .a very;timportantpropertyr of .theproduct he rea men -1 f;ztherill ns mudaccord nglq I Men on nd d s qyery a' ontro calciumHHMQcbntamia nation comprises adding a lignosulfonate thinner oradditiuewhich maybe derived for example fromspent sulfite liquor ashereinabove described, combined. with sodium sulfate, said combinationbeing formed in proportions of "1% to by weightof the sodium sulfatebased on the said spent sulfite liquor solids, the most advantageousproportion being determined .by a pilot test to determine about theproportion necessary to meet the particular produce soluble sulfates.The latter through common ion eifect further reduces the solubility ofcalcium sulfate and hence decreases the calcium ion concentration. Inmany muds it is desirable to maintain low calcium ion concentration toavoid clay flocculation. Regarding the use of bentonite clays, Rogersstates, on page 378 of his text quoted above:

Sodium bentonite -is a highly hydrated, dispersed and ionized member ofthe bentonite salts and possesses good fluid-loss reducing properties.Calcium bentonite, on the other hand, is poorly 'hydrated and dispersedand tends to fiocculate. This flocculation results in fewer but largerparticles which tend to precipitate. As the calcium bentonite forms inincreasingly greater percentage the agglomeration of the particlesand-precipitation result in a decreased viscosity and gel strengths andincreased fluid loss properties. The formation of calcium bentoniteresults in depletion of calcium in the aqueous phase unless replaced :byfurther solution ofthe contaminant]? :Rareuthetically, be itparticularly noted, that the conditions of the Various strataencountered in the drilling of oil and gas wells. areso complex and varyso much and vary-from areaioarea that a pilot test should be madetodetermine what amount. of the product or additive of our invention anddiscovery'is elfective and what amountis mqstrsfii ient asis commonlydone in the; 'drillingopera-.v

tions fon conditioning theparticular mud forthe particular wellei dr ld- Su9h-tes i gmm u y continues-as depend o the-d gr of con ersion. Ashereinbefore;

tated; the alc m m esi m. a mo ium or odium s is l onat r ii iu inlim baemu sz ut not effective in thinning fresh water muds. On the other; handha i n sul nate sa s o i n. lumi u p pper and romium do h s h fre hwater mu s Hence. is: necessary to convert the former salts tothe-,latte-r and the, pr po o nf n er io d t .ine -the etlic u ya e e tioun s; ouv on would e namount ofv con e s o -lathelatter s lt wh h oudina p lfl s a mHd;; hOW- a noticeable, thinning of the mud. Bytwayiofiexample but not limitation, if the salt were fully converted theneven'the additioniof a quarter of a pound per barrel of the convertedsalt would show thinning whereas if say' only -1 (1% -0f -thc sulfonatedsalt were-converted thensit 9f this appl a ion o provide thermal 23would require adding a quantity of the product on the order of severalpounds per barrel to show thinning.

The amount or concentration of the additives of our invention anddiscovery which can be added to drilling fluids by way of conditioningthese fluids to the desired properties will depend on such factors asthe nature of the mud to be treated and the contaminants therein or tobe encountered, the characteristics desired in the mud, and the degreeof purity of the additive and the specific ening effect ondrilling mud.Furthermore, when starch is used for water loss control, it has thedefinite disadvantage of deterioration by microbiological action towhich our additives are very resistant. All of which is of practicalimportance to the well drilling crew. Oxidized lignosulfonates withoutconversion to salts of iron, aluminum, copper and chromium as well asthe unoxidized lignosulfonate salts of these metals can be added in thesame concentration range to drilling mud for effective agents used inpreparing and formulating the additive 10 thinning and water losscontrol.

SPENT SULFITE LIQUOR FROM BLOV PITAND WITH OPTIONAL TREATMENT FERMENTEDAND/R PURI- FIED AND/OR FRACTIONATED AND/OR CONCEN- TRATED TO 20%70%SOLIDS (OR PREFERABLY CONCENTRATED TO 30%50% SOLIDS) AoiiiSa-lt t)Alkaline (7) Acid 1 0xidized(5) (see Appl.fi. l i.69 l,'737) Nan oxidize0x clize Salt tralize (3) (4 (6) Acidify Alum or(l1) with y A1,Gr,Fe,6uFerric baae(2) Lali): Sulfate Alflmfiefiu. exidize 0x1 iae 11m -mudthinner A1 salt or F8 flu or Fraction-late according to our disclosure.For practical purposes, usages of the order of one-quarter of a pound tothirty pounds per barrel are preferred. It is one of the advantages ofour additives that they do not show the thickening of a mud at low usagethat is experienced in the use of quebracho for thinning drilling mud,which thickening is referred to as over treatment. In fact, in the useof quebracho special attention is required to eliminate the danger ofover treatment, which often occurs around 4 to 6 pounds of quebracho perbarrel of mud. With the additive of our invention, prepared from afermented' spent sulfite liquor oxidized with sodium dichromate andconverted to the iron salt, for example, the danger of over treatment isavoided since thickening does not occur below 15 to pounds per barrel.Furthermore, decreases in water loss are observed with usages up to to100 pounds or more per barrel, particularly in gypsum and salt waterdrilling fluid with only slight thickening. Such amounts of additive areused in taking full advantage of our invention and discovery. The aboveemphasizes the universality character of our invention and discovery inthe area of permissible amounts to be employed without adverse action.Thus it is a particular advantage of the additive of our invention thatwater loss values as low as 1 or 2 cc. may be obtained with high usageof the additive without as much thickening in many cases as would occurif water loss were reduced by addition of carboxymethyl cellulose orlike water loss reducers which have a substantial thick- Manifestly, ifthe. starting .material was either raw spent sulfite liquor as it comesfrom the blow pit or if it was fermented spent sulfite liquor withoutfurther purification or fractionation, then any of the products of ourinvention as set forth in the above outline of the possible manifoldtreatments within our invention, may be further purified or fractionatedby adding small increments of lime as herein disclosed or by solventfractionation, application Ser. No. 437,833, filed June 18, 1954, andnow abandoned in favor of U8. Serial No. 703,664. Let it be noted thatfractionation of the spent sulfite liquor provides for selection offractions to yield desired properties in the additive formulated asdisclosed herein.

Thus, to follow through in detail, the starting material may be, aspreviously discussed, either the spent sulfite liquor solids ascontained in the spent liquor as received from the blow pit, or thesesolids refined in various manners, such as by fermentation, limeprecipitation, fractionation, etc. In any case, the solids to be treatedare preferably concentrated to 30% to 50% solution. One method ofoperation, following from point (1) on the chart, is to treat theconcentrated liquor with an acid and heat for example for "l to 2 hoursat to C. At this point if calcium sulfate is precipitated, it may beseparated, depending on the purity desired in the final product. Saidacid treatment may be carried out at less than about pH 4 attemperatures from 50 C. to C. as more fully set forth in our co-pendingapplication Ser. No. 723,036 (U.S.).

armies ,or"it .can:.be further improved. by oxidation, preferably with:an1alkaline reagent such as; potassium permanganate or-"sodiumdichromate as. indicated at-ipoint (3) in. the outline: Either productvmay be useclias: I av liquid, .or' it can; be reducedzto: solids byevaporation and drying. In

either caseythese iproductszimay'beu'sed as thinners for drillin'gmtlds. Alternatively; theprodu'ct can be con-. vetted. tothe salt-.(3a)of iron, chromium, copper, and aluminum, andithis. is outstandingin thefact'thatthe thinningiaction is improved fonboth fresh water and limebase muds;

Again, the acid treatment may be carried out with anacid salt such asferric sulfate, aluminum sulfate, chro- 'mium sulfate, or copper sulfatein such proportions as to also eliect a base exchange -(4-) and'y-ieldaproduct which is effective for thinning all. types of water basedrillingmud. This' product'may also be; oxidized (4a) to'obtai'n furtherimprovement in mudthinning prop ertiesr p Rather than treating with anacid as in (1), the con- ,centrated liquormay be treated directly'with'an'oxidizing agent as' in (5). In this case some-oftheoxidizing agentis"required"to oxidize thesulfur-dioxide which escapes in the caseofacid treatment. This oxidized product may b'e'used as a mud thinner,particularly as a lime base -mud.thinner, or'it may-be converted to theiron, alumi 7 properties are unexpectedly enhanced for thinningi bothlike" and is not sui'table for further usefor the purpose-ofmakingdrillingimud thinners. This heating is conducted while blowing:the solution with: a gaseous medium such as air or nitrogen: Productspreparedin this manner have improvedproperties, said improvement inproperties being somewhat: equivalent to those'attained by our'processof; acid treatment as described inv our US. Ser; bio-723,036.;

.Another and highly. elfective procedure isltofollow process outlinedinour application Ser; Nor'69 4;737involving. treatment with alkali.This product (7) may then" be acidified either'with an-acid '(8-)-andoxidized" (9 .whereby a drilling mud thinner particularly elfectivefor lime-base muds is obtained, or further processed-tot ram the:aluminum, iron, copper. and' chromium saltv (10). Instead of acid,aluminum, iron, copper, and: chromium sulfate may beused 'through whichan economi'-= cab and effective spent sulfite liquor additive (1'1)'isproduced, the properties of which'may be greatlyenhanced by oxidationwith any ofthe' oxidizing agents previously mentioned, to yield(12) anextremely effectiveagent for conditioning all types of water'basedrilling fluids, such as freshwater, lime base, gypsum and oil emulsiontypes;

NLB'. We have discovered that spent sulfite liquor.

components, or, such components chemically modifiedin their. separationfromv spent sulfiteliquor, or intheir, preparation. (.i. e., we findthat materials identified. in general as lignosulfonates respondfavorably .toreour. treats u 1,e11t).;fare' greatl'yzimproved. in:theirelfctivenessas dis- 2.6 1 persingiaagentsz anda for'usjeeinr'drillingzmudsa-byzstreatinmthem-.witluonezorcbothsofstlie-following stepsa if Q (1) Oxidizmgsaidspent'sulfite liquor components (2:)Treati'ng to form a salt havinganyelement selected from thegroup; consisting; of iron; aluminum; chm;-vv, mi'um';andcopperi' g The "order of (the above-.steps or treatment?(oxidizingigon forming a salt) is immaterial. 5

Continuing our treatment against contaminatiom by calcium sulfates, theproduct-.resultingrfrom: both steps.

land 2,;onthe productofistepz, isqtreated with asalt in: theproportionaof; 1.7% to 1-00=%' of the lignosulfonatezsolids ofsaid.spenbsulfite-liquor solids, .-selected fromwthe. group consistingof sodiumsulfate,-; .sodium-.=-.sulfite,. ppe tassiumsodiumttartrate,sodiunroxalate, sodiump;l;os-; pirate, sodium: carbonate, sodium,bicarbonate; aluminum sulfate, iron sulfate, and theircorresponding;potassium: compounds, andtmixturesthereof; V p

Method" 0f"..testing.,--Specific' examples of: treatment together. withtables-showing; results. of "testsz ofv the maee' terials,=.wi1lnowabeset-forth. The methodvofmaking-tlte' tests is that commonlyfollowed in the drilling industry";

The sulfonated. lignin additives of. our inventitm.v may be useddnmanyways, but chief: among these is that re vealedsin' drillinggmuds. For:this purpose 'a-material is required which will bring, about-atlowering" in'vis'cosity'; of the-complex. clay suspension which istermed-thesdrilk ing; mud-,.and will also. serve to decrease-its gelstrength? and. watenloss characteristics. The acceptedi'methods.forevaluating, materials a to ascertain their utility ,for; drillingmuds are described in the publication-entitled? American PetroleumInstitute Code 29, ThirdEdition, May 1950.-Recommended' Practice on.Standard .Field; Procedure for Testing; Drilling" Fluids. Thismanuahlis: prepared and published. by theAmerican: Petroleumglirestitute; Division: of Publication; Dallas, Texas, andzisi usedthroughout-the industry for-testing drillingxmudsn In making .thelaboratory'testson. drilling-muds:-accord+s ing to theproceduresimentionedi above, it is necessaryttor use a'clayorcombination of clays. Ingeneral, clays:are'r- There has beennocorrelation-between chemicalanalysiss and clays and their suitabilityfor drillingpurposes. (The Science; of Petroleum, volume 1,. page..458,. 1938;. Oxford University Press: ('London).) Although. clays;have been divided into several. classes according to their: chemical andphysical form, the materials encountered: or used in drilling-muds aremixtures of said. claysz andz. so ithas become practically accepted todefinerthesema: terials in terms of what is termed yield value. cordingto practice then- (Principles of Drilling: Mud. Controlfi 8th: edition,pages 2 and: 3, published'by'thea American Association. of; Oil WellDrilling Contractors; Dallas, 1951) clays. are defined in terms ofyield-value, which is thenumber. of barrels of 15 cprmud thatcanbe'prepared. from. a ton ofmateriall along with water. Thus v in theexamples, we refer totheuseof natural clay and define thev yield valueto characterize theJtype of clay which would give similar results.

Byfollowingthe standard methodsidentified above-and" using claysof.defined yield value, theefiicacyofthe sulfa; nated lignin additives ofour invention is measured in;

terms of initial gel strength, viscosity, ten-minutegelstrength,.and:water loss.

The Stormer viscometer has been used almost-universal; I lyinmakmgviscosity measurements according we nie:

spasms "27 measures two factors of viscosity called "yield value" offluids and plastic viscosity which are so related that two times theplastic viscosity plus the yield value is proportional to the viscosityat 600 r.p.m. Since the plastic viscosity is essentially constant forany one mud, the variation of the yield values indicate directly thevariation of viscosity and therefore the yield value is reported in thetables where the measurements were made with the Penn instrument.

Generally only the yield value of the drilling mud is affected by theaddition of thinners. Yield values are reduced by drilling mud thinnersbut plastic-viscosity is affected very little. The plastic viscosity canonly be changed by adding to ,or removing water from the mud. The FannV-G meter type of instrument is preferred for drilling muds since itindicates whether thinners are needed to lower yield or Whether water isneeded to decrease plastic viscosity.

The viscosity factor yield value of fluids defined above should not beconfused with yield value of a clay which has been defined hereinaboveas the number of barrels of 15 cp. mud that can be prepared from a tonof clay along with water.

Mud test procedures.The following mud test procedures describe in detailthe mud preparation and testing procedures used. The clays defined inthe test procedures given below were used in all of the first twelveexamples except Examples H and III in which another but similar clay wasused having a yield value of 36, that is, the clay would yield 36barrels of 15 cp. mud per ton of clay. Clays in other examples aredefined therein but have about the same yield value.

Lime mud test procedure.--Sixty grams of a commercial rotary drillingclay with a yield value of 45 barrels of 15 centipoise mud per ton ofclay were mixed with 325 milliliters of distilled water in a HamiltonBeach No. 30 Drinltmaster mixer for 15 minutes at 15,000 r.p.m., andthen aged by rolling, i.e., agitating in pint bottles overnight at roomtemperature. The aged mud was broken over" to a limed mud by adding 6grams of calcium hydroxide, 6 milliliters of sodium hydroxide solutioncontaining 0.25 grams sodium hydroxide per milliliter, and thesulfonated lignin containing material additive to be tested (each gramadded equivalent to 1 pound per barrel) and mixing for 5 minutes at highspeed. Broken over is a term used in the industry to denote theprocedure and the accompanying change in properties which occur when anexcess of calcium hydroxide and sodium hydroxide is added to a clay withintimate mixing as next above set forth. The mud was then returned tothe bottle and again rolled overnight at room temperature, and finallymixed another 5 minutes immediately before determining viscosity, gelsand water loss by the standard procedure of the American PetroleumInstitute.

Fresh water mud test procedure.--Thirty grams of a commercial sodiumbentonite rotary drilling clay with a yield value of 92 barrels of 15centipoise mud per ton of clay were mixed with 335 milliliters ofdistilled water in a Hamilton Beach No. 30 Drinkmaster mixer at 15,000r.p.m. for 15 minutes and then aged by rolling overnight in pint bottlesat room temperature. The thinner additive (each gram added equivalent to1 pound per barrel) and sodium hydroxide to give the desired pH werethen added, the mud mixed 5 minutes, and again rolled overnight ,at roomtemperature. A final 5 minute mix was made immediately before measuringviscosity, gels, and water loss by the standard methods of the AmericanPe-' troleum Institute. The mud may be returned to the bottle and rolleda further 24 hours at 150 F. and then retested to obtain information onthe etfect of temperature. Higher temperature aging is described in'Example XVII.

Gyp mud test pr0cedure.The gyp (or gypsum base) mudtest procedure is thesame as the fresh water mud 28 test procedure'except that 6 grams (eachgram added equivalent to 1 pound per barrel) of plaster of Paris (CaSO.%H O) were added together with the thinner additive, and the mud wassubsequently mixed for 20 minutes instead of 5 minutes.

Oil emulsion test pr0cedure.-The base mud is prepared as desrribed aboveand may be any of the types such as lime base, gypsum, fresh water andsalt water muds. After adding the thinner additive being tested andmaking the standard tests for gels, viscosity and water loss, 10 to 20%by weight of diesel oil is mixed into the mud with a high speed mixer at15,000 r.p.m..

and the resulting oil in water emulsion mud tested for gels, viscosityand water loss by the standard API procedures. Note that the termthinner is used in the art in reference to agents or additives forreducing the viscosity of drilling mud.

EXAMPLE I This example illustrates the procedure for fractionating spentsulfite liquor by lime precipitation to obtain cal cium lignosulfonatefractions with better drilling mud thinner properties than the originalspent sulfite liquor.

One thousand grams of spent sulfite liquor solids in 10% water solutionwere heated to about C. and lime slurry was added grams of calciumoxide), whereupon an appreciable amount of organic precipitate wasobtained. (Temperature not critical, 85 C. equals temperature of liquoras received from blow pit.) This small precipitate settled rapidly andwas separated by decanting and recovered as a cake by centrifuging thethick slurry. Further fractions were recovered successfully in the samemanner by adding 25 gram increments of lime and removing theprecipitates formed. The precipitates were washed by decantation withsaturated lime water to prevent resolution by water during washing, thenredissolved by adding sulfuric acid to pH 5 to 6 and dried afterremoving by filtration calcium sulfate. Results of the fractionation areshown in Table I.

Table I of Example I FRACTIONATING OF SPENT SULFITE LIQUOR BY LIMEPRECIPITATION Cumulative Yield of Lime Added, Calcium Percent of Ligno-Diffusion Fraction No. Spent Sulfite pH sultonate, Co-

Liquor Solids Percent of efliclent,

riglnally Spent Sulfite mmJ/day Present in Liquor Solution Solids Inredissolving, other acids than sulfuric may be used in lowering the pHof the separated precipitate and bringing about solution. It may bepreferred to use an acid such as carbonic, sulfurous, or oxalic, whichare characterized by giving insoluble compounds with calcium wherebyexcess calcium is removed from the product, In some types of drillingmud, it is desirable to have the additive as free as possible of solublesalts, so that acids such as hydrochloric and acetic which form solublecalcium salts would not be desirable, although for some purposes theycould be used. Also the precipitate can be dissolved by adding a saltwhich gives by base exchange an insoluble calcium salt, i.e., sodium,iron, chr0- mium, copper, aluminum, magnesium ammonium, etc. sulfates,phosphates, oxalates, sulfites, etc. Thus the desired iron, copper,aluminum, and chromium salts can be made directly.

It will be understood that any fraction will dissolve rapidly.

29 if the pH is lowered-below 'the. p Hcat which it was precipitated,but the-additiomof sulfuric acid. to providepl-I. 5 or16- ishelpfulingiving quick solutions and'zapproximately neutral products. Thus, wehave discovered" that it is possible to divide the lignosulfonates ofspent sulfite liquor intoseveral'fractions by adding as the first step arelatively small or minute amountor an increment of lime, that is, 130.grams in 10,000 grams of spent sulfite liquor of 10% concentrationwhichcaused toprecipitate 'an appreciable, i.e., recoverable, amount oforganic precipitate, namely-14.4%, and also we discovered, contrary toexpectations, that said amount settled out surprisingly ThisprecipitateWasseparated out as fraction No. 1. .Then, as a second step'a smallamount or increment of lime, i.e.,- 25. grams- (CaO) was added to theremaining solution, whereupon. a second. small. amount, 4.5% oftheoriginal spent sulfiteliquor solids, was precipitated-and thislikewise rapidly. This-was separated. successively the above stepswererepeateduntil six fractions were removed. I

Differences in drilling mud thinner properties of the fractions, themolecular weights of which are-illustrated and identified. in Table 2 ofExample I.

Table 2 of Example I LIMED MUD TESTS N FRACTIONS OF SPENT SULFITE LIQUORPREPARED BY .LI-M'E" PRECIPITATION A v 1b.] lnitial 10 WaterFractlonNo'. bbl; GeL; Vise. Gel, Loss;

gms; g ns. cc.

Original spent sulfite liquor. 4 100 29.0 250.. 21 .9 1 V 4- 20 43. 2 3016. 7 2 4' 0' 15.0' 60 f 1410 3- 4 0 h 9.8 401 14. 2 4 4 0 11.0: 60 15.05 4 0' 12-.3 100' 15. 3 6 4 14.0 160. 16.2

' Table 1 of Example I shows that the calcium lignosulfonates werefractionatedinto fractions of' -diiferent molecularweight as-showrr bythe difiusion-coefficient data. Tame-2 of Example' l shows that fraction3 was the most-eifective drilling mud thinner because of-"thegreatest-reduction in the' properties noted which particw larly meansthat less Water is required to give'a pump-'- able mud drillingvfluidwithia minimum of water loss all of which properties are of.mostiundamentalimporh ance in oil and gas well drillingr Of course, thefrac tionationmaybe-varied-by addingsmaller amounts of lime to givesmaller fractions characterized by having morei-uniform molecularweightdistribution, or a frac tion may bemade including parts: offractions 2'. and. 4

in;- fraction .3. Thus ismade' most manifest the: wider scope,advantages,- and discovery. I

Also, this example. illustrates .thatourinVention and. discoveryteaches. thatby' proper manipulation: theor-' ganic. precipitate canbeobtainedbetween pH 10.0 and: 12.0 from spent sulfite liquor'uponi'addinglime, andcarr flexibility of our. invention and be recovered asanumber of calcium .lignosulfonate: fractions of-difierentmolecularweights; We also havediscovered thatthesediiferentfractionsexhibit diiferent'improved; properties, thereby making it possible toselect thel zi'mprovedfraction in supplying a product exhibiting the.exact ormore'nearly'exact properties required fora particularapplication;

7 EXAMPLE II To illustrate the: improvement in drilling ,mudthinner Iproperties. obtained by chlorinating. spent sulfite liquor according toour invention and discovery, samples of fermentedspent sulfite liquorwere concentrated to 30% solidszbyevaporation and then commercialchlorine gas was bubbled into. theliquor'until weight increasescorresponding to -1, 2, Sand 4% of the solids of thefermented spentsulfite liquor solidswere obtained. Samples chlos rinated wlths.1%.--and=2%achlorinezhadpiliii and-a s respectively and were dried at 60 C. The3%.:ande49ifi chlorinated samples had pH. 1.4 and. 1.0 respectively andvwere neutralized to pI-I-2.0- with sodium hydroxide before drying at 60C. to avoid deterioration ofithe components of the spent sulfite liquor.The dried samplesxwere' tested as limedmud thinners and the resultsareset-forth= in- I Table 1 of Example II.

Table 1 of Example]! CHLORINATION OF A FERMENTED SPENT SULFITE LIQUOR"LIMED MUD TESTS USING 6 POUNDS PERJBLXRREI'Z In all casesof'chlorinatin'g, the pH" should -"be=- adjusted by theaddition of analkali before drying 'to a value of more than 220 and less th'anrlO-ZO.

Table l of" Example 11' showsa progressive improv' ment'i'n mud thinnerproperties as the percentageoi-cli tine-is increased up to 4% chlorine.When less. of the additive isadded to themud, some ofthe mud thihnerproperties of the sample chlorinated with"4% chlorineare poore'r thanobtained with the sample. chlorinated with3'% chlorine. Thus, it'becomesnecessary-1o purify chlorinated spent sulfite liquor (i.e., for"exampl'eyre move calcium chloride) when more chlorinei.-is used than 4%,otherwise-better products are notobtained;

EXAMPLE IIIv To: illustrate the fractionation of achlorinated-spentsulfite liquor by lime precipitation a: sampleof spente-sul' fite-iiquorwas chlorinated by'bubblingsinchlorineunt-il the-Weight increased by anamount equal to'i43 of the weight: of spent sulfite liquor solids and:then. wasre: covered limeprecipitation in the same manner as. describedin' Example 1. Fractionation dates-are. shown in the followingtablelTizble 1 ofEXampl-J'Il FRACTIONAL LIME'RREOIPIT'ATION 0F GHLOR'INA'PEDLIGNOSULFONATES-FROM CHLORINAYIIED" spam: SUL- FLTELI UOR 43%aOH-LORINEON THE BASIS OF THE SPENT sULrL'rE LIQUOR SOLIDS Yield,.Percent of SpentYield Per- Sulfite Liqeentof Spent- Coefficlent, uor Solids SulfiteLlqmm. /d:ry'

uorsolids Cumulative.

Difluslo'n 1 Fraction No:

By comparison with Table 1 in Example I; it is seen that the chlorinatedlignosulfon'ates beginprecipitatin'g at a much lower pH than the calciumlignosulfonates of the original spent sulfite liquor. The resulting wide.pH range of. precipitation makes possible a closer control offractionation reproducibility than is obtainable" with limeprecipitation of spent sulfite liquor-solids.

Comparative drilling mud testsiweremade on the iiags COLIPARATI'VE LIMEDMUD THINNING PROPERTIES OF OHLORINATED LIGNOSULFONATE FRACTIONS OB-TAINED B.Y LIL/IE PRECIPITATION Limed Mud 10% Diesel Emulsion Samplelb./ bbl.

LG. Visc. 10G. W.L. LG. Visc. 10G. W.L.

Originalfermented g gg ggy 4 as 25.0 195 19.1 Thick not a 13.0 00 18.212 29.0 o 10.5 (ore chlorination). 4

. o 15.5 20 15.0 10 46.0 240 9.3 -i g g 13.2 0 0 26.2 10 7.2

0 0 27. 70 9. 2 g 8 10.7 0 20.0 7.3 1 16.9 0 25.0 9. 2 0 .2 a2 .3 a2 a.0 0 8.5 20.8 0 20.0 80 11.6

The spent sulfite liquor chlorinated with 43% of chlorine beforefractionation and without purification to remove calcium chloride onaddition to lime base mud gave a thicker mud than did untreatedfermented spent sulfite liquor.

The data of Table 2 of Example III shows that the chlorination of thespent sulfite liquor by passing of chlorine gas through spent sulfiteliquor renders the spent sulfite liquor components especially effectivein conditioning lime base muds. Particularly are they eifective inincreasing the thinning property, as will be seen by noting the resultsrespecting viscosity for fractions 1-4. All of said fractions areimproved over the original spent sulfite liquor viscosity figure of25.0. Fraction 2 shows a viscosity of 9.8 which is the pre ferredresult. Thereafter, fractions 3 and 4 show an increase in viscositywhich indicates that the fraction 2 gives the optimum result in loweringviscosity. Referring to the other properties of fraction 2 in comparingthese with the other properties of the fractions 1, 3, and 4, it is tobe noted that the properties of fraction 2 are optimum. In other words,it is not only to viscosity that fraction 2 gives optimum results, butin general to other properties. In addition, it is noted that thesefractions are highly efiective in producing oil emulsion type muds andwhereas the optimum properties occurred with fraction 2 for the regularlime base drilling mud in making oil emulsion type lime base muds, thefraction 3 gave the greatest lowering in viscosity although fraction 2itself Was highly effective as compared with either fraction 1.or 4 orespecially the original sulfite liquor.

The outstanding teaching of Table 2 of Example 111 is that it shows thatdifferent fractions of the spent sullite liquor have varying propertiesand therefore that it is of the utmost importance, in using spentsulfite liquor where definite properties are desired, to fractionatesaid liquor and determine which fractions will give the best propertiesfor the particular problem in hand. Thechlorination treatment is thusseen to play a very important part in providing fractions of the spentsulfite liquor. It greatly facilitates the procuring of such fractions,and furthermore, the very important feature is revealed that thefractions of the chlorinated product are of greatly improved character.In other words, the effectiveness of the lignosulfonate compo nents isgreatly increased by chlorination.

EXAMPLE IV To illustrate the yields of chlorinated lignosulfonatesobtained by lime precipitation purification of chlorinated spent sulfiteliquor by the addition of varying amounts of chlorine to 45% fermentedspent sulfite liquor, the following table is presented.

, v32 Table 1 of Example IV SPENT SULI IIE LIQUOR OHLORINATION AND BECOVERY OF PURIFIED LIGNOSULFONATES LIlNIE PRE- CIPITATION YIELD ChlorineUsed in Lime Precipitation Chlorination, Yield of Chlorinated Percent ofSpent Products, Percent of S Liquor Original Spent Solids Suhite LiquorSolids 1 Yield includes chlorine combined with spent sulfite liquorsolids.

The data of Table 1 of Example IV shows that for chlorine usage up toabout 30% of the spent sulfite liquor solids the cost of chlorineaddition is compensated by an increased yield of product in amountapproximately equal to the weight of chlorine added. Moreover, suchchlorine addition gives an improved product. Furthermore, the tableshows that the addition of more chlorine over the 30% figure does notprovide additional yield.

In general, the chlorination can be conducted in diluted, i.e., in thespent sulfite liquor as received from the blow pit, or in concentratedspent sulfite liquor.

EXAMPLE V The improvement in thinning action in lime base mud providedby oxidation of spent sulfite liquor solids with several oxidizingagents is shown in the following example: Solutions of 100 grams ofspent sulfite liquor solids in 300 milliliters water were mixed coldwith solutions of the various oxidizing agents to give theconcentrations of oxidizing agent based on spent sulfite liquor solidsshown in Table 1 of Example V. The solutions were then heated at C. forone hour to insure complete reaction, dried at 60 C. in a flat shallowpan and ground to a powder for testing. The results of adding thesepowders to lime base muds are shown in the following table. In theseexperiments a lime base mud was prepared as described herein above usinga clay having a yield value of 45. In all cases the results involve theaddition of 4 pounds of the powdered product per barrel of mud.

Table 1 of Example V EFFECT OF OXIDIZED SPENT SULFI'IE LIQUOR ON LIMEBASED MUD Sample LG. Vise. 10 G. W.L.

Original fermented spent sulfite liquor 29. 0 250 21. 9 3% H201(hydrogen peroxide) 60 20.0 200 20. 2 6 H2O 30 15.0 20.2 2% KMn04(potassium permanganate) 65 24.0 230 18. 5 O 35 18. 7 190 17.4 7 16.2150 18.4 0 15.0 130 10.0 85 25.2 280 19.6 15 20 17.3 10 16. 5 150 17.630 22. 5 15.8 75 26. 5 250 19.0 50 19.0 260 19.6

Table 1 of Example V shows improvements in mud thinning obtained byoxidation with several oxidizing agents. In further experiments beyondthe scope of said table we have discovered improvements in mud thinningfor products from spent sulfite liquor oxidized with up to 50% by weightof oxidizing agents. The dichromates are particularly useful, since inaddition to oxidation the chromic ions formed in the reaction form saltsor complexes with the spent sulfite liquor components and provideproducts of greater thinning capacity particularly in fresh water mudsthan are obtained with the other oxidizing agents. Chromic acid behavesin the same manner as shown in Table 2 of Example XXV.

Whereas chlorine is an oxidizing agent and has been so referred tohereinabove, and it is a very inexpensive chemical relatively "speaking,"however, its 1186 requires furthenpurifieation of the oxidized andchlo'r'inated s ent .slilfite'liquor solids rby the use .of'limeprecipitation. In contrast, the oxidizing agents listed in Table 1 ofi'Examp1e"V ma'ybe used without such purification step, i.e,, without,resorting ,to the l jlime precipitation step. 'Thus, our discoveryincludes the use of hydrogen peroxide, potassium permanganate,,tpotassiufn dichromate, sodium peroxide and other agents asfsetforth'herein, whichtare 7'5 cc. "of'a solution '"containing 20' grams ofaluminum :sulfate (17% M .After wfiltering off the calcium sulfate,theJacidit y offthe. solution f wa's acljusted to ;pH f3:8by.addingj2f5, grams sodium hyroxide'in solujttio'n and the 1 productdried for "testing. V

v The abilitytofthis aluminumsalt of the spent-sulfite liquor components'to thin sodium bentonite at'"-p'H .9;5, i;e.,fia freshwatergmud, isshown 'in the following table. I J'ablel qfi-Exwmple-VI 'THINNING ton'WA'BER .MUD BY CALCIUM FLAJND While spent su'lfiteliquor as receivedfrom the blow -pit contains calcium salts, nevertheless such saltsprovide little or no thinning action for the m'ud. This fact also hasbeen observed for ammonium, magnesium and so- 7 dium sa'ltsof the'lignosulfona'tes. on the other hand, Tabled of'Example shows that .thealuminum salt is compa'rableito quebrachounder the conditions of thetest.

It is-acadmic that quebra'cho is the preferred material for use inconditioning fresh watermuds (being usedto the ext'entto'f 30,000 :to40;000"tons per year for such purpose), and accordingly, toprovideaproduct which is I comparable'fromazwaste product like'spentsulfite liquor,

"is a meritorious cont-fibution to the art.

v ile thisillustrat-ion of Example fYLh'asbeen neede to the contrastingproperties of'ytthe aluminum salt with thoseof the usualsoecalledtcooking-.bases, calcium, am-;

monium, sodium, and magnesium similar results: have been observed withth iron, copper and chromium salts as set forth ,in the followingexample, namely VII.

.t EXAMPLE v11 Gne'method of preparation of iron, chromium, copper andaal'um'in'umsalts of s'u'l'fonated Ii nin-containingma:

j te r'ials derived from wood pulping liquors is described in thisexample fliy way of example the starting material I was chosen to ,giveproducts with particularly effective ithinning properties for aqueoussuspension of clayma- ,terial used for drilling mud. This startingmaterialgwas a conc'entrated :and fermented calcium .base1spent slilfiteliquor -given-an alkaline-pretreatment according to .the 7 method of ourinvention, US. patent -=application 'Se r.

- No. 694,737. The preparations were made"and"the'prod t-u'cts tested asfollows: One thousand grams of concentrated calcium zbase Spent sulfiteliquor derivedfrom paper pulp production and havinggthe .fermentablecarbohydrates substantially removed ,by fermentation'and havinganalkalinity valuejabout' pH 4; containing 47 .5 pounds of dissolvedsolids per 100 pounds 'of' solution, were this'soluti'on was dilutedwith 89cc. of water to make a 25% solutiontand reacted with solutions(25% in Water) :containing 20 grams of aluminu'mfsiilfate 117% :Al Q 20grams of ferric sulfate (Fe (-SO .-9I-I O), :35 grams of copper:sul'fate (Cu'SOQSHO), pr'fzograms of chromium potassium sulfate(C1K(SO4)2I1'2'H O),fl'espectively, and the resulting precipitates 'ofcalcium sul- 'fate =werefiltered ofi. The'produc'tswere drie'dat 60. C.and tes'tedas "fresh watermud'thinners using 155 pounds of thinner perbarrel of mud.

It is clear from the results's'et forth in the following table thatthinning action is obtained with all'of' thesc salts Of the spentsulfite liquor-componentscomparable with that of quebracho infresh'water'muds at a pH'of both 935 and 12. The 'pre'ferred's'alt,'basedon its elficiency as a thinnen is the iron 'salg alth'ough in mudshaving a pH iof -l2-the chromium salt shows even more enhancedproperties, ire, it provides a product withmore effective prop-"ertiesyparticularlyin that it gives agreater viscosity lowerin'g for-agiven concentration.

Thus, again-is esta'blished'the meritorious contribution to the artby'the presenti'invention and 'discovery,'in providing apr'oduct fromspent sulfiteliquor,whieh product has' properties comparable with thatof 'quebra'cho which has been the preferred material for conditioningfresh water rr'mds.

It -is"to be noted' thatwhen--these=produets are pr pared frem spen'tsulfite liquor some acidity- "isdeveloped during base exchange mustsubsequently be neiitralized as 'herei-ribefore described i Ex'amp'le-I.Itfis therefore-adyantag'eous to add -the sodium hydroxide to the spent*siiIfite liquor'fir-st byway of preparing our additive accord ing toUS. applioation Ser. No.--391, '1-16"which thereby providesamore-idesirable'"starting inaterial 'andfat the same time providesthe-sodinm hydroxide necessary for :the fina'l neutralization.

Table .1 of Example V11 v 'THIN'NING or .FRE SH WATER:MUDYBYMJUMINUM,mow

;O0-BP.-ER=;AND CHROMIUM SALTS OF-SBENT SULFITE 'LIQ'UOR ADDITIVE V[usvapplieutlon Serial No. 694,737.}]

pH :akgentakdded W.L

L Orighialhrugl(no agent) ';52;-5 170' it 9.2 ,Alurnhmmfsalt 3,- 31-.5,. 400; .9.-9 v 'Iron'salt 7' 30.3 140 17.0 1. Ghromiumsalt. 10 35.1,10.05 17.7 Copper salt... 5 37.0 t 130, 8.7 t Quebracho '20 40.6 170 t7.9 .Orlginalmud (um-agent) Very thick-too thick,

measure Y 60 '63.0 450 8 12t0.....-..'. 5; 27.7 150. 7 0, 22.5 7 Coppersaltt. 0 25.5 8 'Quebracho -5 '2115 1160 7 iusiapplicationSerialNo.-391,116, filed November 9, 1953, abandoned I tln lfgggortotSerlalNo. 694;733tand-Serial No. 694,737, tboth'filed November i EXAMPLE'vm the fresh water mud thinnin'g 'properties of iron salts offermentedspent 'stilfitefliquor solids, a number of I'samplejscrimesalts were p'repa'red as described infExa'i-np le and then oxidizedby'hea'ting for one hour 1at 19Q5ji'Cawith;

2, *4, I6, .8 and 1 0% of potassium dichrornate beforedrying at 60C. Theresults of freshwater mudltsts made at; pH 12.0 with 0.5 pounds ofthinner perfbarrel are mod follows: (the p'H Was'cho'sen fortheseitest'sibecause 35 Table 1 of Example VIII EFFECT OF DEGREE OFOXIDATION OF THINNER ON FRESH WATER MUD THINNING The data of Table 1 ofExampleVIII show improvement through continued decrease in viscosity ofthe fresh water muds at pH 12.0 as the degree of oxidation increases upto 10% of sodium dichromate. The concentration of spent sulfite liquorsolids afiects the amount of oxidant which can be advantageously addedwithout formation of an insoluble gel. In this experiment, sodiumdichromate was added as a 25% solution in water to spent sulfite liquorhaving a total solids concentration of about 40% by weight. Thus, acontinued improvement in drilling mud thinner properties was discoveredand this effect of increase of oxidant is shown in Table 1 of ExampleVIII. Furthermore Table 2 of Example VIII illustrates that water solubleproducts were obtained with much larger amounts of oxidant by addingdilute solutions of the oxidant to dilute spent sulfite liquor. Table 2establishes that the improvement in drilling mud thinning propertiescontinued as the amount of oxidant increased to about 14% of sodiumdichromate. At this point the viscosity of the mud being tested began toincrease whereas the water loss continued to decreaseto an addition ofabout 18% of the sodium dichromate Thus, the water loss factor continuedto improve at least to 18% sodium dichromate addition. Moreover at 50%sodium dichromate addition the treated mud is appreciably benefited incomparison with the untreated gypsum mud.

Table 2 of Example VIII.Range of dichrmate.--'Ihe following experimentswere made to illustrate the effect of varying degrees of oxidation ongyp-mud thinning properties of iron salts of fermented spent sulfiteliquor solids. Samples were madeusing various amounts of sodiumdichromate and tested as drilling mud thinners.

The preparation was started by making a quantity of evaporated,fermented spent sulfite liquor alkaline to pH 8 with sodium hydroxide,and then heating in an open container at 80 to 90 C. for 24 hours, whileadding sodium hydroxide at intervals as needed to maintain the pH at8.0. Next 15% of ferric sulfate (24.5% Fe) was added as a 30% solutionin water, and finally 7% of sodium dichromate dihydrate was added as a25% solution with vigorous agitation at a temperature of 60 C. Alladditions are based on the weight of the fermented spent sulfite liquorsolids. The mixture was heated to 90 C. in a hot water bath andcentrifuged to remove the precipitate of calcium sulfate. The clarifiedliquor was then divided into several parts, each diluted to solids and10% solutions of sodium dichromate added to increase the dichromate to14.0, 18.0, 20.0, 21.0 and 24.0% respectively by weight of the saidspent sulfite liquor solids. Sulfuric acid was added to control theacidity at pH 3.5 while adding the sodium dichromate.

Two additional samples were prepared with the addition of 40% and 50% ofsodium dichromate to a sample of fractionated fermented spent sulfiteliquor solids containing 17% of reducing substances determined asglucose and the remainder of the spent sulfite liquor solidspredominantly low molecular weight lignosulfonates. Said sample offractionated spent sulfite liquor was obtained by alcohol fractionation.The sodium dichromate was added as a cold 2.5% solution to a cold 2.5%solution of the said spent sulfite liquor solids while adding sulfuricacid to maintain the pH at 3.0. Since the high dichromate usage resultsin chromium ion concentrations equivalent to the addition of excesschromium sulfate over that necessary for base exchange of the calcium inthe start ing material, no salt such as chromic sulfate or ferricsulfate was added to give fresh water thinning properties; The sulfuricacid added to maintain pH 3.0 was suflicient to precipitate the calciumas calcium sulfate. The latter was removed but does not necessarily haveto be removed for effective use in gyp-mud. Calcium sulfate should beremoved for use in fresh water mud.

The product liquors as set forth above were heated to C. to insurecompletion of the oxidation and then dried at 60 C. for testing.

The oxidized products were tested as thinners for a gypsum base mudusing 6.0 pounds per barrel of thinner to compare their relative valueas mud thinners and as water loss reducing agents. The mud test results,Table 2 of Example VIII, show the water loss results improve onincreasing the sodium dichromate to about 18% Mud thinning resultsbecome poorer above 7% of sodium dichromate, but said oxidized productsare operable as drilling mud thinners over the range of 1% to 50% sodiumdichromate.

An especially useful eifect of using larger amounts of sodium dichromateoxidation is improved stability to high temperatures. This effect isshown in Table 3 where the properties of muds thinned with 4.0 poundsper barrel of the samples were prepared as above with 4% and 14% ofsodium dichromate respectively are compared in gypsum base mud afteraging the mud for 20 hours at 350 C.

The mud test results, Table 3, show that the sample prepared with 4% ofsodium dichromate increased on aging in yield, gels and water losswhereas the sample prepared with 14% of sodium dichromate actuallydecreased in yield and gels on aging at 350 F. and did not increase asmuch in water loss. A special and demanding need for mud thinners stableto high temperatures has been recognized as higher temperatures wereencountered on deeper drilling.

Table 2 of Example VIII EFFECT OF AMOUNT OF SODIUM DICHROMATE OXIDA-TION ON MUD THINNING PROPERTIES [Untreated gyp-mud, yield 19.0, APIwater loss 32.4.]

Percent Mud Yield API Water Percent Sodium Dichrornate r in Value AtLoss At Based on SSL Solids Product 6#/Bbl. 6#/Bb1- Thinner ThinnerTable 3 of Example VIII THERMAL STABILITY AT 350 F.

Rolled Overnight, Room Temp.

Sample #lbbl. pH LG. PV Y 10 G. W.L.

4% dichromate 4. 0 8.2 2. 0 0. 0 8.0 14. o '10. 0 14% dichromate 4. 0 8.2 3. 0 5. 5 6. 0 9. 0 8. 4

Aged 20 hrs., 350 F.

' 4% dichromate 4.0 8 2 22.0 6.0 30 0 '43. 0 28. 0 14% dichromate 4.0 75 1. 0 6.0 1 0 7. 0 18. 3

PV== plastic viscosity. Y=yield value.

EXAMPLE IX This example illustrates on the one hand, the improvement infresh water mud thinner properties and, on the other, the poorer resultsobtained in limed muds by adding an excess, i.e., more than the amountof iron, aluminum,

' *barrels-oTflS .cp. mud per ton .Qfclay seams copper or chromium sulfate necessary to base exchange the calcium -in spent sulfite 'li'quorsolids. Spentxsulfite liquor solids (about 40% concentration) wereoxidized with 8% I ofpotassium dichromate by. heating in aqueous{solution at 95 .C. for one .,hour. Iwo samples .01',. PO1? tions ofsaid-oxidized spent-sulfite liquor were .prepared,

one wasmixed with 20% (base exchange?) =T8I1d the other with-35% by"weight of-aluminum-sulfate (17% A1 ltwill be noted that about 23% isequivalent foribase exchange. Thusythe second sample had an excess over{base exchange of'-ab;out 12 After -filtering off the fprecipitate .ofcalcium sulfate; the products were at 80 C. and tested as fresh waterand limed .mud

thinners. The fresults areshown in -the following 'table;

@EEFEGT OF ".THE AMOUNT H(I.E. CONCENTRATION) '.0-,F ALUMINUM SULFATE.QN..TBINNINGYIRQ EBZIT B T 'i'lG Vise. 1o GI" will.

4 2o% aluminum sulfate 15.40.; .170 s. v 35% aluminum sulfate... 6533"170" 0; Base fresh water mud 80 52.5 170 9.

LIMED MUD 'rns'rs AT nzutrnRinnL.

- 20%aluminumsuliate 115.0"; .110; I 20. 0 1 35% aluminum sulfate '2033.0 240 20.

It is apparent from these figures that. the cifect er the concentrationof aluminum sulfate added in making the aluminum salt-on. the thinningaproperties ofathe product is different for fresh water mudsthan-for.lime-basemuds.

In the case of fresh water muds the initial gel and viscosity are :bothimproved, that :is, lowered, whereas .inzthe ilimed r.equired fora baseexchange .in spent sulfite liquor. Sll'1'lj1al' results are obtainedwith an excess of chromium sulfate aluminum sulfate orpcopper sulfate.Thesulfate ion is essentially removed .by neutralizing with lime.

Fermented spentsulfite liql nr was.reacted with various amounts offerric sulfate ---(-24. 5% Fey-from to 80% by weight of the spent liquorsolids. The ferric sulfate wasdissolvedinwaterito make about a 30%solution and then poured into-the hot concentrated (about a 48% totalsolids) spent liquor with stirring.

After digesting overnight at 85 -9 0", the. acid mixture neutralized topH 4 by adding lime slurry, centrifuged to: remove calcium sulfate, -anddried in .an air .stream at 60C. V H

"The dried products were tested .as .mudthinners in both fresh water andgypsum base'mu'ds. These muds were prepared ashereinbe'fore'described'using 451511bs.

I per "barrelof a' mixture of clays containing 6 parts-0f a commercialdrilling clay having -a yield -alue of 45 'barrels'of 15 'cp. ,mud perto'no'f clay and one-part'of commercial drilling clay having iffyieldvalue of 1.95-

In thecase of the ffresh water mud test two poundlper barrel ofthesample was added to the mud. and sufficient "sodium hydroxide addedto adjust the pH of the mudt'o 9.5 and niixed'i'ors'minutes ena'highspeed mixer. The

mudswereithenplaced in sealed glassbottles. rolledpvefnight at .roomtemperature "and finally 'heat'aged by roll ing for 20 hours at 150 Themudswerethen tested 7 for yield values and gels by the standard APIgtestmethod. The test results are shown in Table 2 of Example IX.

To test the samples in "gypsum mud, 4 lbs. perb'arrel of .the sample'together'with .6 'lbs.'perbarre'l of plaster of Paris were added to the."mud togetherwithgsufiicient sodium hydroxide .(1 ml..=0.25 g. 'NaOH)to obtain a final pH value of 8.2. The muds wereimixedifor 20 minutes athigh speed inza Hamilton Beach Drinkmaster, No. 30 mixer. Thefmuds werethen placedfin sealed "bottles, rolled overnight at room temperature andheat aged by rolling f0r20 hours at 150 F. The muds were 7 then testedfor'yield values, .gels and API water loss. The

test results are shown in Table 2 of Example IX.

With referencelfto Table 2 of Example lX,'it iss'hown that substantialimprovement is attained in; both fresh water and gypsumbasemuds by theaddition of excess ferric sulfate, and that the greatest.improvement inall. properties 'is attained in the range of 20% .to 60% addition offerric sulfate (24.5% 'Fe') on the fermented spent sulfite liquorsolids. Thisaddition is equivalent to about 17% to 52% :of the anhydrousfer-ricsulfate, the ;lower figure being a little more than'required forbase exchange.

'Thechoice of the percentage employed is determinedby -the particularpropertymost desired. 7

About 17.7'-%:o'f ferric sulfate (24.5 Fe) v is'requiredto:complete'lylbase exchange iron for calcium in the spent sulfite liquorand the amount added above 17.7% is 'thereforeexcessferricsul'fate'above-baseexchange;' That the excess iron-is boundchemically by th'espent "sulfite liquorsolidscan be shown'by the failureof ironto pre- 'cipitate when solutions-of the test samples are -madealkaline by the addition of's'odium hydroxide" product therefore appearsto'have the charaeterisncisof a complex salt. Thus, although we speak ofthe metals being present as cations, because of the possibility'o'f theformation of a complex salt, the metals may not beentirelypresent ascations. But in any case, the metal ispreSe'nt T in soluble form and weherein refer to.,thes e metals as being present as cations,.and as beingassociatedwith the ,sulfonated lignin-containing material.

Similar results were obtained with ferrous sulfate in place of ferricsulfate.

Table. 2 of Example IX EFFECT ON THINNING PROPERTIES OF INCI KEAS ING VTHE CONCENTRATION OF FE RRIC SULFATE Ferric Sulfate Addition Yield Valu10 Minute -Wa,ter {Percent of SSIH-Solids) of Mud (lh./- G lbil "Izoss,I 1100 sq.it.) 1 10055;. ft.) wcc.

{lestsswith sodiumbase mud- Base mu 54.0. 107.0 12. 15 35.5- j 48.0 10.34.0 ---;52.0 Y 19. 20.5 11.5 -.9.' 15. 0 43. 0' --'9.- 18.0 42.0 r :10.29.70 66. 0. "1 1.

..S.S L spent sulfite liquor .in this case termented. .2

Table 3 of Example'IX. The-limit of the-'addition'of the sulfatesalts-of iron, ;a'luminum,.copper and chroniiurn to the oxidized saltsis different-for each salt, beca'useiit gvaries for each metal, andalsowith the degree of 11ydra-- tion of the sulfate salts. To obtain anindicatio'n df the maximum amountof these'salts which canbeiadded anex*peiiment was-made in which oxidized spent 'sulfiteiliquo'r 7 sampleswere prepared containing the chemical equivalent The

1. A DRILLING FLUID COMPOSITION COMPRISING A SUSPENSION OF A CLAYEYMATERIAL IN AN AQUEOUS MEDIUM CONTAINING AN EFFECTIVE DISPERSING AMOUNTOF A SOLUBLE, OXIDIZED SALT OF A SULFONATED LIGNIN-CONTAINING MATERIAL,SAID SALT HAVING A CATION SELECTED FROM THE GROUP CONSISTING OF IRON,ALUMINUM, CHROMIUM, COPPER AND MIXTURES THEREOF.
 38. A DRILLING FLUIDCOMPOSITION COMPRISING AN AQUEOUS SUSPENSION OF A CLAYEY MATERIALTHINNED BY A SOLUBLE ADDITIVE PREPARED FROM SULFONATED LIGNIN-CONTAININGMATERIAL OBTAINED FROM SPENT SULFITE LIQUOR BY A PROCESS WHICH COMPRISESTRATING SAID SULFONATED LIGNIN-CONTAINING MATERIAL IN AQUEOUS SOLUTIONWITH A METAL ION SELECTED FROM THE GROUP CONSISTING OF IRON, ALUMINUM,CHROMIUM, COPPER AND MIXTURES THEREOF SAID METAL ION BEING ADDED IN ANAMOUNT EFFECTIVE TO PRODUCE SAID THINNING, AND SAID METAL ION AND SAIDSULFONATED LIGNIN CONTAINING MATERIAL BEING CAPABLE UPON DRYING THEREOFOF FORMING A SALT.
 47. A DRILLING FLUID COMPOSITION COMPRISING ASUSPENSION OF A CLAYEY MATERIAL IN AN AQUEOUS MEDIUM CONTAINING ANEFFECTIVE DISPERSING AMOUNT OF A SOLUBLE ADDITIVE PREPARED BY A PROCESSWHICH COMPRISES OXIDIZING A SULFONATED LIGNIN-CONTAINING MATERIAL WITHAN OXIDIZING AGENT HAVING AN OXIDIZING POWER STRONGER THAN AN OXIDATIONPOTENTIAL OF ABOUT-1.3.